[lilliput-jdk21u:lilliput] Integrated: 8307907: [ppc] Remove RTM locking implementation

[Roman Kennke]

Hi all,

This pull request contains a backport of commit [de8aca27](https://github.com/openjdk/jdk/commit/de8aca27ba87427307186ffd25c029b5c6dbc82e) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Martin Doerr on 15 Jun 2023 and was reviewed by Matthias Baesken, Richard Reingruber and Thomas Stuefe.

Thanks!

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Commit messages:
 - Backport de8aca27ba87427307186ffd25c029b5c6dbc82e

Changes: https://git.openjdk.org/lilliput-jdk21u/pull/27/files
  Webrev: https://webrevs.openjdk.org/?repo=lilliput-jdk21u&pr=27&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307907
  Stats: 864 lines in 15 files changed: 0 ins; 842 del; 22 mod
  Patch: https://git.openjdk.org/lilliput-jdk21u/pull/27.diff
  Fetch: git fetch https://git.openjdk.org/lilliput-jdk21u.git pull/27/head:pull/27

PR: https://git.openjdk.org/lilliput-jdk21u/pull/27