Allow customizing slow JVM shutdown thread dump for Java test runner

[donce]

Description of the feature request:

Currently, BazelTestRunner dumps all threads if JVM exit takes longer than 5 seconds (printStackTracesIfJvmExitHangs in BazelTestRunner.java). This duration is hard-coded and this cannot be changed.

In theory, this sounds reasonable, though we do have some long-running E2Es, which also execute real shutdown hooks and it can take longer than 5 seconds, resulting in thread dumps in a happy-path.

If there's an issue with a shutdown and it actually hangs, these logs are not really useful as well, because they are emitted after 5s since shutdown, but by the time test timeout happens - some (or even most) of the threads might have already been shutdown, and the emitted thread dump is actually misleading.

Can this duration be configurable?

Which category does this issue belong to?

Java Rules

What underlying problem are you trying to solve with this feature?

Redundant and misleading thread dumps for long-running E2E tests.

Which operating system are you running Bazel on?

No response

What is the output of bazel info release?

No response

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

No response

[hvadehra]

This sounds reasonable to me. A PR would be welcome. Following the same pattern as for the test suite name is probably the simplest.