RFR: 8360540: nmethod entry barriers of new nmethods should be disarmed

[Martin Doerr]

Adding `disarm` calls as ZGC and ShenandoahGC already have. I will need reviews from GC experts. Tier1 tests have passed and I'll run more tests, but experts may know about potential problematic side effects.

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Commit messages:
 - 8360540: nmethod entry barriers of new nmethods should be disarmed

Changes: https://git.openjdk.org/jdk/pull/25982/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25982&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360540
  Stats: 9 lines in 3 files changed: 9 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25982.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25982/head:pull/25982

PR: https://git.openjdk.org/jdk/pull/25982