RFR: 8365190: Remove LockingMode related code from share

[Leonid Mesnik]

On Tue, 2 Sep 2025 08:24:10 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. After that, a number of PRs has been integrated which has removed all `LockingMode` related code from all platforms (except from zero, which is done in this PR).
> 
> This PR removes `LockingMode` related code from the shared (non-platform specific) files. It also removes the `LockingMode` variable itself.
> 
> Passes tier1-tier5 with no added problems.

svc part looks good.

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Marked as reviewed by lmesnik (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27041#pullrequestreview-3181274100