A jdk.VirtualPinnedEvent JFR event is recorded by Object::wait when a virtual 
thread waits in Object.wait while pinned. The posting of the event in 
ObjectMonitor::wait is done after waiting but it can block again in 
enter/ReenterI before it re-acquires. If that happens then the event duration 
won't be accurate, and for the off-list case, the enter may be contended and a 
jdk.VirtualPinnedEvent event will be recorded for contended monitor enter. The 
changes to fix this are small: move the post of the event for Object.wait to 
end of the wait function, and only post an event for contended monitor enter 
when not waiting.

I've added a test to check the pinned event that is recored for several 
contended monitor enter and Object.wait cases. It checks the event duration and 
that only one event is recorded for each case.

-------------

Commit messages:
 - Min duration check needs to have some tolerance
 - Rename test, check more event fields
 - Filter out VirtualThread.getAndClearInterrupt
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/22718/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22718&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346120
  Stats: 494 lines in 2 files changed: 485 ins; 5 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22718.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22718/head:pull/22718

PR: https://git.openjdk.org/jdk/pull/22718

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