[CI] SimpleNetty4TransportTests testWatchdogLogging failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #8467 / openjdk23_checkpart1_java-matrix
• elasticsearch-periodic #8449 / openjdk23_checkpart1_java-matrix

Reproduction Line:

./gradlew ":modules:transport-netty4:pooledTest" --tests "org.elasticsearch.transport.netty4.SimpleNetty4TransportTests.testWatchdogLogging" -Dtests.seed=36392B7A04EF95E3 -Dtests.locale=kl -Dtests.timezone=Jamaica -Druntime.java=23

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: expected not to see no logging but did
Expected: <1L>
     but: was <0L>

Issue Reasons:

• [main] 2 failures in test testWatchdogLogging (0.6% fail rate in 330 executions)
• [main] 2 failures in step openjdk23_checkpart1_java-matrix (50.0% fail rate in 4 executions)
• [main] 2 failures in pipeline elasticsearch-periodic (50.0% fail rate in 4 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

Pinging @elastic/es-distributed-coordination (Team:Distributed Coordination)

[ywangd]

The warning message is

the following threads are active but did not make progress in the preceding [5s]: [elasticsearch[TS_A][transport_worker][T#14]]

But in the hot threads dump, this thread is already idle

 0.0% [cpu=0.0%, idle=100.0%] (0s out of 500ms) cpu usage by thread 'elasticsearch[TS_A][transport_worker][T#14]'
  10/10 snapshots sharing following 10 elements
    java.base@23.0.2/sun.nio.ch.EPoll.wait(Native Method)
    java.base@23.0.2/sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:121)
    java.base@23.0.2/sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:130)

And the thread we expect to be reported as stuck is elasticsearch[TS_A][transport_worker][T#13].

I think the issue here is similar to #113734 in that there might be other threads temporarily not making progress. We need to tighten up the pattern matching for the log message.