RFR: 8369444: JavaFrameAnchor on PPC64 has unnecessary barriers

[David Briemann]

No hardware barriers are necessary. All members are volatile and the profiler is run from a signal handler and only observers the thread its running on.

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Commit messages:
 - 8369444: JavaFrameAnchor on PPC64 has unnecessary barriers

Changes: https://git.openjdk.org/jdk/pull/27768/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27768&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369444
  Stats: 9 lines in 1 file changed: 3 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27768.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27768/head:pull/27768

PR: https://git.openjdk.org/jdk/pull/27768