RFR: 8345294: test/jdk/java/lang/Thread/virtual/RetryMonitorEnterWhenPinned.java timeout with JTREG_TEST_THREAD_FACTORY=Virtual

[Doug Lea]

Accommodate compensations when checking for missed signals; add a better test for this.

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Commit messages:
 - test starvation with monitors
 - Accommodate uncompensates in deactivate

Changes: https://git.openjdk.org/jdk/pull/22543/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22543&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345294
  Stats: 68 lines in 2 files changed: 61 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/22543.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22543/head:pull/22543

PR: https://git.openjdk.org/jdk/pull/22543