RFR: 8365190: Remove LockingMode related code from share

[Fredrik Bredberg]

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.

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Commit messages:
 - 8365190: Remove LockingMode related code from share

Changes: https://git.openjdk.org/jdk/pull/27041/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27041&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365190
  Stats: 1268 lines in 50 files changed: 6 ins; 1129 del; 133 mod
  Patch: https://git.openjdk.org/jdk/pull/27041.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27041/head:pull/27041

PR: https://git.openjdk.org/jdk/pull/27041