RFR: 8340838: Clean up MutableCallSite to use explicit release fence instead of AtomicInteger

[Claes Redestad]

On Tue, 24 Sep 2024 20:21:48 GMT, Chen Liang <liach at openjdk.org> wrote:

> This implementation code was written in JDK 7, before storeFence was available in JDK 8. We should update this legacy code to make it clear.

Marked as reviewed by redestad (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/21169#pullrequestreview-2326497113