Revert "tcp: switching to the new pool (#12180)"

[ggreenway]

This reverts commit f50fba1.

Confirmed that switching the runtime override listed in that commit fixes the crash, so reverting as per advice in #12180.

[2020-07-20 16:12:49.616][19388][info][main] [source/server/server.cc:664] starting main dispatch loop
[2020-07-20 16:12:57.451][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:104] Caught Segmentation fault, suspect faulting address 0x0
[2020-07-20 16:12:57.451][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:91] Backtrace (use tools/stack_decode.py to get line numbers):
[2020-07-20 16:12:57.451][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:92] Envoy version: de43823f3956bede6c077a7da2783cc46bf1b50c/1.16.0-dev/Modified/DEBUG/BoringSSL
[2020-07-20 16:12:57.522][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #0: Envoy::SignalAction::sigHandler() [0x5630cd2d0bac]
[2020-07-20 16:12:57.522][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #1: __restore_rt [0x7f7d0fcf0390]
[2020-07-20 16:12:57.582][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #2: Envoy::TcpProxy::Filter::UpstreamCallbacks::onEvent() [0x5630cbf9f722]
[2020-07-20 16:12:57.641][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #3: Envoy::TcpProxy::Filter::onPoolFailure() [0x5630cbfa2228]
[2020-07-20 16:12:57.700][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #4: Envoy::Tcp::ConnPoolImpl::onPoolFailure() [0x5630cc8412f1]
[2020-07-20 16:12:57.749][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #5: Envoy::ConnectionPool::ConnPoolImplBase::purgePendingRequests() [0x5630ccab4f36]
[2020-07-20 16:12:57.795][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #6: Envoy::ConnectionPool::ConnPoolImplBase::onConnectionEvent() [0x5630ccab49ac]
[2020-07-20 16:12:57.841][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #7: Envoy::ConnectionPool::ActiveClient::onEvent() [0x5630ccab60fb]
[2020-07-20 16:12:57.888][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #8: Envoy::Tcp::ActiveTcpClient::onEvent() [0x5630ccaa1e75]
[2020-07-20 16:12:57.933][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #9: Envoy::Network::ConnectionImplBase::raiseConnectionEvent() [0x5630cc744141]
[2020-07-20 16:12:57.981][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #10: Envoy::Network::ConnectionImpl::raiseEvent() [0x5630cc736205]
[2020-07-20 16:12:58.026][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #11: Envoy::Network::ConnectionImpl::closeSocket() [0x5630cc736007]
[2020-07-20 16:12:58.074][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #12: Envoy::Network::ConnectionImpl::onWriteReady() [0x5630cc7399c0]
[2020-07-20 16:12:58.119][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #13: Envoy::Network::ConnectionImpl::onFileEvent() [0x5630cc73933e]
[2020-07-20 16:12:58.165][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #14: Envoy::Network::ConnectionImpl::ConnectionImpl()::$_6::operator()() [0x5630cc73db2e]
[2020-07-20 16:12:58.212][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #15: std::_Function_handler<>::_M_invoke() [0x5630cc73d9f1]
[2020-07-20 16:12:58.257][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #16: std::function<>::operator()() [0x5630cc72ce9a]
[2020-07-20 16:12:58.305][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #17: Envoy::Event::FileEventImpl::mergeInjectedEventsAndRunCb() [0x5630cc72beeb]
[2020-07-20 16:12:58.351][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #18: Envoy::Event::FileEventImpl::assignEvents()::$_1::operator()() [0x5630cc72c24a]
[2020-07-20 16:12:58.398][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #19: Envoy::Event::FileEventImpl::assignEvents()::$_1::__invoke() [0x5630cc72bff6]
[2020-07-20 16:12:58.444][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #20: event_persist_closure [0x5630cd1fa0ae]
[2020-07-20 16:12:58.491][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #21: event_process_active_single_queue [0x5630cd1f96d8]
[2020-07-20 16:12:58.536][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #22: event_process_active [0x5630cd1f3e9a]
[2020-07-20 16:12:58.583][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #23: event_base_loop [0x5630cd1f2d4c]
[2020-07-20 16:12:58.629][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #24: Envoy::Event::LibeventScheduler::run() [0x5630cc7572b8]
[2020-07-20 16:12:58.675][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #25: Envoy::Event::DispatcherImpl::run() [0x5630cc7230da]
[2020-07-20 16:12:58.722][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #26: Envoy::Server::WorkerImpl::threadRoutine() [0x5630cc6ff27d]
[2020-07-20 16:12:58.767][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #27: Envoy::Server::WorkerImpl::start()::$_4::operator()() [0x5630cc7009dc]
[2020-07-20 16:12:58.815][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #28: std::_Function_handler<>::_M_invoke() [0x5630cc70089d]
[2020-07-20 16:12:58.860][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #29: std::function<>::operator()() [0x5630cae7d0ce]
[2020-07-20 16:12:58.907][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #30: Envoy::Thread::ThreadImplPosix::ThreadImplPosix()::{lambda()#1}::operator()() [0x5630cd332ac2]
[2020-07-20 16:12:58.953][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #31: Envoy::Thread::ThreadImplPosix::ThreadImplPosix()::{lambda()#1}::__invoke() [0x5630cd332a95]
[2020-07-20 16:12:58.953][19417][critical][backtrace] [bazel-out/k8-fastbuild/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #32: start_thread [0x7f7d0fce66ba]
Segmentation fault (core dumped)

[ggreenway]

Force-push to fix DCO

[ggreenway]

@alyssawilk Here's the config I used that caused the crash. There is nothing listening on either of the cluster's ports (10000 and 10001).

  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 8080
    filter_chains:
    - filters:
      - name: envoy.tcp_proxy
        config:
          stat_prefix: tcp_vip_stats
          cluster: cluster1
          max_connect_attempts: 2
          access_log:
            - name: envoy.file_access_log
              config:
                format: "[%START_TIME%] duration_ms=%DURATION% downstream_remote_address=%DOWNSTREAM_REMOTE_ADDRESS% upstream_local_address=%UPSTREAM_LOCAL_ADDRESS% upstream_remote_address=%UPSTREAM_HOST% downstream_tx_bytes=%BYTES_SENT% downstream_rx_bytes=%BYTES_RECEIVED% flags=%RESPONSE_FLAGS%\n"
                path: "tcp_access.log"
  clusters:
  - name: cluster1
    connect_timeout: 0.25s
    type: STATIC
    lb_policy: round_robin
    transport_socket:
      name: envoy.transport_sockets.tls
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.transport_sockets.tls.v3.UpstreamTlsContext
        common_tls_context:
          tls_params:
            tls_minimum_protocol_version: 'TLSv1_2'
            tls_maximum_protocol_version: 'TLSv1_3'
    hosts:
      - socket_address:
          address: 127.0.0.1
          port_value: 10000
      - socket_address:
          address: 127.0.0.1
          port_value: 10001
admin:
  access_log_path: "/dev/null"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 8081

node:
  id: the_id
  cluster: the_cluster