RFR: JDK-8307810: Consistently use LockingMode instead of UseHeavyMonitors [v4]

[Daniel D. Daugherty]

On Wed, 10 May 2023 15:49:38 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> [JDK-8291555](https://bugs.openjdk.org/browse/JDK-8291555) phased out UseHeavyMonitors in favor of LockingMode=0. We forgot to apply these changes to PPC and S390. 
>> 
>> Since UseHeavyMonitors implies LockingMode, but not vice versa, we now have a mismatch if JVM is started with LockingMode=0 but without UseHeavyMonitors. That leads to crashes.
>> 
>> The patch fixes that, and in addition makes sure that if LockingMode=0 is set, we are setting UseHeavyMonitors too.
>
> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into JDK-8307810-use-lockingmode-instead-of-useheavymonitors
>  - Merge branch 'master' into JDK-8307810-use-lockingmode-instead-of-useheavymonitors
>  - Dont modify UseHeavyMonitors
>  - JDK-8307810-use-lockingmode-instead-of-useheavymonitors

Sorry we missed finding the rest of the UseHeavyMonitors uses
during the work on JDK-8291555.

Switching those uses to the appropriate check of LockingMode is the
right solution. We want UseHeavyMonitors to fade into the sands of
history...

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Marked as reviewed by dcubed (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13900#pullrequestreview-1421026099