quiche: do not arm stream_idle_timer_ if the stream is closed

[danzh2010]

Commit Message: stream_idle_timer_ is armed to timeout the sending of the bufferred response payload in the quic stream send buffer after the end stream is buffered in the stream. But today this timer is armed even if the the encoding of the payload causes the stream to be closed, in which case the timer can never be cancelled till the stream destruction with ASSERT hit as below:

[2022-08-12 22:23:38.843][12][critical][backtrace] [./source/server/backtrace.h:104] Caught Aborted, suspect faulting address 0x50e8d0000000c
[2022-08-12 22:23:38.844][12][critical][backtrace] [./source/server/backtrace.h:91] Backtrace (use tools/stack_decode.py to get line numbers):
[2022-08-12 22:23:38.844][12][critical][backtrace] [./source/server/backtrace.h:92] Envoy version: 0/1.24.0-dev/test/DEBUG/BoringSSL
[2022-08-12 22:23:38.858][12][critical][backtrace] [./source/server/backtrace.h:96] #0: Envoy::SignalAction::sigHandler() [0x3480b28]
[2022-08-12 22:23:38.858][12][critical][backtrace] [./source/server/backtrace.h:96] #1: __restore_rt [0x7f94b072c200]
[2022-08-12 22:23:38.872][12][critical][backtrace] [./source/server/backtrace.h:96] #2: Envoy::Quic::EnvoyQuicStream::~EnvoyQuicStream() [0x2a2fe98]
[2022-08-12 22:23:38.885][12][critical][backtrace] [./source/server/backtrace.h:96] #3: Envoy::Quic::EnvoyQuicServerStream::~EnvoyQuicServerStream() [0x2a78058]
[2022-08-12 22:23:38.899][12][critical][backtrace] [./source/server/backtrace.h:96] #4: Envoy::Quic::EnvoyQuicServerStream::~EnvoyQuicServerStream() [0x2a77d30]
[2022-08-12 22:23:38.912][12][critical][backtrace] [./source/server/backtrace.h:96] #5: Envoy::Quic::EnvoyQuicServerStream::~EnvoyQuicServerStream() [0x2a77d69]

This change check stream close in this case, so that the idle timer will not be armed for closed streams.

Risk Level: low
Testing: new unit test
Docs Changes: N/A
Release Notes: N/A
Platform Specific Features: N/A

[jmarantz]

/assign-from @envoyproxy/first-pass-reviewers

[repokitteh-read-only]

@envoyproxy/first-pass-reviewers assignee is @tonya11en

🐱

Caused by: a #22689 (comment) was created by @jmarantz.

see: more, trace.

[RyanTheOptimist]

Nice! Thanks for doing this