RFR: 8364141: Remove LockingMode related code from x86 [v4]

[Fredrik Bredberg]

On Thu, 7 Aug 2025 09:23:37 GMT, Fredrik Bredberg <fbredberg at openjdk.org> wrote:

>> Since the integration of [JDK-8359437](https://bugs.openjdk.org/browse/JDK-8359437) the `LockingMode` flag can no longer be set by the user, instead it's declared as `const int LockingMode = LM_LIGHTWEIGHT;`. This means that we can now safely remove all `LockingMode` related code from all platforms.
>> 
>> This PR removes `LockingMode` related code from the **x86** platform.
>> 
>> When all the `LockingMode` code has been removed from all platforms, we can go on and remove it from shared (non-platform specific) files as well. And finally remove the `LockingMode` variable itself.
>> 
>> Passes tier1-tier5 with no added problems.
>
> Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update three after review

Thanks everyone for the reviews.

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PR Comment: https://git.openjdk.org/jdk/pull/26552#issuecomment-3178335696