There are problems calling WaitForRunningWorkers when we
call quit().
First, suppose the main thread first calls quit(),
and the worker thread calls quit() after the main
thread calls quit(), then sched_yield to wait for
quit_once_ updated to ONCE_STATE_DONE. However
the main thread is WaitForRunningWorkers to wait
for the worker thread to join, thus causing deadlock.

Second, suppose the worker thread calls quit() and empty
the running_workers_ by WaitForRunningWorkers, then
the main thread calls `onExit(isolate, true)` to dispose
the platform and other global data, which will crash other
running workers.

Bug: v8:12219
Change-Id: I333e5aad431daefb1c163f69e66d8e9d5e9bf754
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3518908Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79525}