build: eliminate precompiled headers from bazel build.

[htuch]

Since Bazel doesn't support precompiled headers (bazelbuild/bazel#1215),
we actually suffer a slowdown rather than speedup by having all files implicitly include
precompiled.h in the Bazel build. I found ~10% performance improvement on my workstation, going from
181s to 163s for a "bazel build //test/..." from a "bazel clean" state.

This patch makes all includes now explicit. This will slowdown the cmake build, but since this is
not long for this world it seems alright. The header reordering in this patch was achieved using #793.
The addition of the missing headers in each file was done using a modified version of the tool in #793,
which substituted in headers based on simple substring matches (e.g. whenever it saw std::string in
a file, it added #include ). Here's the patterns I ended up using that seemed to work:

sys_extra_includes = [
('std::runtime_error', 'stdexcept'),
('strcmp', 'string.h'),
('strcasecmp', 'strings.h'),
('std::unique_ptr', 'memory'),
('std::shared_ptr', 'memory'),
('std::unordered_set', 'unordered_set'),
('std::transform', 'algorithm'),
('std::vector', 'vector'),
('std::regex', 'regex'),
('spdlog::', 'spdlog/spdlog.h'),
('fmt::format', 'spdlog/spdlog.h'),
('std::string', 'string'),
('uint32_t', 'cstdint'),
('uint64_t', 'cstdint'),
('std::array', 'array'),
('sockaddr_un', 'sys/un.h'),
('sockaddr_in', 'netinet/ip.h'),
('std::chrono', 'chrono'),
('std::list', 'list'),
('std::multimap', 'map'),
('std::unordered_map', 'unordered_map'),
('std::stringstream', 'sstream'),
('std::condition_variable', 'condition_variable'),
('std::mutex', 'mutex'),
(' ::close', 'unistd.h'),
('inet_ntop', 'arpa/inet.h'),
('inet_pton', 'arpa/inet.h'),
('htonl', 'arpa/inet.h'),
('setsockopt', 'sys/types.h'),
('setsockopt', 'sys/socket.h'),
('TCP_NODELAY', 'netinet/tcp.h'),
('SIGTERM', 'signal.h'),
('SIGPIPE', 'signal.h'),
('std::function', 'functional'),
('std::ifstream', 'fstream'),
('std::ofstream', 'fstream'),
('std::forward_list', 'forward_list'),
('std::atomic', 'atomic'),
('std::cerr', 'iostream'),
('hostent', 'netdb.h'),
(' bind(', 'sys/types.h'),
(' bind(', 'sys/socket.h'),
('std::ostream', 'iostream'),
]

extra_includes = [
('MOCK_METHOD', 'gmock/gmock.h'),
('MOCK_CONST_METHOD', 'gmock/gmock.h'),
('MATCHER_P', 'gmock/gmock.h'),
('ON_CALL', 'gmock/gmock.h'),
('using testing::', 'gmock/gmock.h'),
('testing::Test', 'gtest/gtest.h'),
('EXPECT', 'gtest/gtest.h'),
('\nTEST(', 'gtest/gtest.h'),
('\nTEST_F(', 'gtest/gtest.h'),
('\nTEST_P(', 'gtest/gtest.h'),
('HeaderMapImpl', 'test/test_common/printers.h'),
('Buffer::', 'test/test_common/printers.h'),
('RespValue', 'test/test_common/printers.h'),
]

[mattklein123]

looks good but obviously needs master merged now

[mattklein123]

Yay GH. This change is actually merged.

[mattklein123]

Closing, I guess?