RFR: 8358621: Avoid using a spinlock as the synchronization point returning from native in CPU Time Profiler

[Johannes Bechberger]

Simple optimization to avoid busy waiting in safepoint handlers.

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Commit messages:
 - Improve busy waiting

Changes: https://git.openjdk.org/jdk/pull/26314/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26314&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358621
  Stats: 8 lines in 1 file changed: 7 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26314.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26314/head:pull/26314

PR: https://git.openjdk.org/jdk/pull/26314