jmx-dev RFR: 8188784: javax/management/notification/BroadcasterSupportDeadlockTest.java - TEST FAILED: deadlock

[Kevin Walls]

This test incorrectly fails, although rarely, thinking its "thread 2" has deadlocked.
A change of sleep will likely fix this, but there are other issues, so cleaning up the test a little.

Remove the probe for the ManagementFactory class, to check we are on jdk5 or later. 8-)

When sleeping, sleep 100, not 1ms, we don't need to spin fast and actually race with the other thread.

We have a 1000 iteration loop, but don't seem to use it.  We only check once then either return (pass), fail, or break (which is also fail).  Use the loop to check for the status change, which is likely what was intended.

Show the stackframes on all failures.

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Commit messages:
 - 8188784: javax/management/notification/BroadcasterSupportDeadlockTest.java - TEST FAILED: deadlock

Changes: https://git.openjdk.org/jdk/pull/18687/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18687&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8188784
  Stats: 36 lines in 1 file changed: 9 ins; 18 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/18687.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18687/head:pull/18687

PR: https://git.openjdk.org/jdk/pull/18687