RFR: 8352116: Deadlock with GCLocker and JVMTI after JDK-8192647

[Albert Mingkun Yang]

Using a new lock (`JNICritical_lock`) in `GCLocker::block` to resolve a deadlock issue. The root cause of the deadlock is that holding `Heap_lock` while waiting in `GCLocker::block` is unsafe.

The new lock is held from the start of `GCLocker::block` to the end of `GCLocker::unblock`. This requires adjusting `Heap_lock`'s rank to allow acquiring `Heap_lock` while holding `JNICritical_lock`. The most important changes are in `gcVMOperations.cpp` and `mutexLocker.cpp`.

Test: tier1-8; verified failure can be observed 2/2000 and pass 8000 iterations.

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Commit messages:
 - tmp
 - gclocker-nested

Changes: https://git.openjdk.org/jdk/pull/24407/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24407&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352116
  Stats: 31 lines in 4 files changed: 20 ins; 7 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/24407.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24407/head:pull/24407

PR: https://git.openjdk.org/jdk/pull/24407