[jdk17u-dev] RFR: 8290004: [PPC64] JfrGetCallTrace: assert(_pc != nullptr) failed: must have PC

[Martin Doerr]

Clean backport of the memory barrier addition. Omitted cleanup which would require other changes which are not in 17u.

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

Commit messages:
 - Backport cb6e9cb7286f609dec1fe1157bf95afc503870a9

Changes: https://git.openjdk.org/jdk17u-dev/pull/545/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=545&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290004
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/545.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/545/head:pull/545

PR: https://git.openjdk.org/jdk17u-dev/pull/545