Withdrawn: 8284811: Shrink critical section of JNICritical_lock

[duke]

On Wed, 13 Apr 2022 08:29:29 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> This refactoring around gc-locker consists of two commits:
> 
> 1. Remove `_debug_jni_lock_count` because `verify_critical_count` already verifies #threads in critical regions. `_debug_jni_lock_count` doesn't introduce anything new.
> 
> 2. Shrink the critical section associated with `JNICritical_lock` to accesses to `_needs_gc` and nothing else.
> 
> Test: tier1-6

This pull request has been closed without being integrated.

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PR: https://git.openjdk.org/jdk/pull/8218