RFR: 8342673: Test serviceability/jvmti/events/NotifyFramePopStressTest/NotifyFramePopStressTest.java failed: waited too long for notify

[Chris Plummer]

Fix deadlock with suspending the main thread while it is in Thread.join() to join the thread that is suspending it. The suspending thread then waits for a FRAME_POP event on the main thread, but that never happens because it is suspended.

Testing in progress. Running the test 100 times on all supported platforms, including separate run with `-Xcomp`.

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Commit messages:
 - Fix deadlock during join()

Changes: https://git.openjdk.org/jdk/pull/21650/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21650&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342673
  Stats: 7 lines in 1 file changed: 7 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21650.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21650/head:pull/21650

PR: https://git.openjdk.org/jdk/pull/21650