RFR: 8365190: Remove LockingMode related code from share [v2]

[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.

Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:

  Update after review

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27041/files
  - new: https://git.openjdk.org/jdk/pull/27041/files/71038b71..3c1b56c5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27041&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27041&range=00-01

  Stats: 17 lines in 4 files changed: 1 ins; 4 del; 12 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