[jdk22u] RFR: 8325587: Shenandoah: ShenandoahLock should allow blocking in VM

[Liang Mao]

Clean backport of fixing rare long hand shake while mutator threads in heavy contention on ShenandoahLock.

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Commit messages:
 - Backport 492e8bf563135d27b46fde198880e62d5f1940e8

Changes: https://git.openjdk.org/jdk22u/pull/192/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk22u&pr=192&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325587
  Stats: 67 lines in 3 files changed: 48 ins; 1 del; 18 mod
  Patch: https://git.openjdk.org/jdk22u/pull/192.diff
  Fetch: git fetch https://git.openjdk.org/jdk22u.git pull/192/head:pull/192

PR: https://git.openjdk.org/jdk22u/pull/192