RFR: 8338995: New Object to ObjectMonitor mapping: PPC64 implementation [v4]

[Martin Doerr]

> PPC64 implementation of [JDK-8315884](https://bugs.openjdk.org/browse/JDK-8315884).

Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:

  Consistently use CCR0 in compiler_fast_lock_lightweight_object and compiler_fast_unlock_lightweight_object

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20922/files
  - new: https://git.openjdk.org/jdk/pull/20922/files/571601f7..6581e5ab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20922&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20922&range=02-03

  Stats: 25 lines in 1 file changed: 0 ins; 0 del; 25 mod
  Patch: https://git.openjdk.org/jdk/pull/20922.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20922/head:pull/20922

PR: https://git.openjdk.org/jdk/pull/20922