[jdk21u] RFR: 8315869: UseHeavyMonitors not used

[Paul Hohensee]

On Tue, 17 Oct 2023 09:44:28 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Unclean backport to clean up JDK 21 and make future backports more clean. The removed option is `develop`, so there is no compatibility problems.
> 
> The uncleanliness comes from the need to `-XX:+UnlockExperimentalVMOptions` the flag.
> 
> Additional testing:
>  - [x] `grep -R UseHeavyMonitors src/`, no hits
>  - [x] `grep -R UseHeavyMonitors test/`, no hits
>  - [x] macos-aarch64-server-fastdebug, affected tests pass
>  - [x] macos-aarch64-server-release, affected tests pass

Marked as reviewed by phh (Reviewer).

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PR Review: https://git.openjdk.org/jdk21u/pull/265#pullrequestreview-1688592153