RFR: 8367982: Unify ObjectSynchronizer and LightweightSynchronizer [v2]

[Coleen Phillimore]

On Mon, 27 Oct 2025 00:29:38 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update after review
>
> src/hotspot/share/runtime/synchronizer.cpp line 655:
> 
>> 653:     // installed in the object header.
>> 654:     return install_hash_code(current, obj);
>> 655:   }
> 
> This merging of the OMT and non-OMT `FastHashCode` does not seem related to the `lightweight` renaming. I found it very hard to convince myself of the equivalences here so would prefer to see this in a separate PR.

This was refactored to share with lightweight synchronizer but now doesn't need to be factored out.  The same code is below.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27915#discussion_r2481294207