RFR: 8372650: Convert GenericWaitBarrier to use Atomic<T> [v2]

[Aleksey Shipilev]

On Fri, 28 Nov 2025 08:55:45 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Please review this change to GenericWaitBarrier to use Atomic rather than
>> directly applying AtomicAccess to volatile members.
>> 
>> Testing: mach5 tier1-5
>
> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
> 
>   undo unintended load_acquire

Looks fine now, thanks.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28527#pullrequestreview-3518102337