fix: gracefully close unused workers

[NoamGaash]

This patch suggest a fixing issue #30504 by gracefully terminating the worker before exiting the process

[github-actions]

Test results for "tests 1"

27476 passed, 672 skipped
✔️✔️✔️

Merge workflow run.

[dgozman]

Thank you for the PR! Unfortunately, we cannot remove the process.exit() call after some timeout, because graceful termination may misbehave and leave zombie processes.

There should be a different fix for this, most likely the one that waits for graceful termination in the regular worker shutdown from the dispatcher. However, I'll have to experiment with it first to figure out the right fix. We'll look into this for the v1.45 release.

[NoamGaash]

Investigation notes:

• the dispatcher calls worker.stop() because _isWorkerRedundant(worker) evaluates as true.
• the worker is considered to be redundant because isWorkerRedundant sees that the _queuedOrRunningHashCount is zero - there are no queued or running jobs, as the worker teardown doesn't count as a job

I'm a little stuck with this investigation, as I can't really figure out how exactly the worker-scoped fixtures are registered.