RFR: 8307907: [ppc] Remove RTM locking implementation

Fri Jun 9 16:39:47 UTC 2023

This PR removes RTM code for PPC64. The instructions are not supported by Power10 processors.
The situation is even worse in Power9 compatibility mode on Power10. The VM detects RTM to be available, but the processor is unable to complete any transaction successfully.
The feature had so many problems and we never supported it in production.

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Commit messages:
 - 8307907: [ppc] Remove RTM locking implementation

Changes: https://git.openjdk.org/jdk/pull/14398/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14398&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307907
  Stats: 701 lines in 12 files changed: 0 ins; 691 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/14398.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14398/head:pull/14398

PR: https://git.openjdk.org/jdk/pull/14398