[jdk23] RFR: 8333716: Shenandoah: Check for disarmed method before taking the nmethod lock

[Neethu Prasad]

This pull request contains a backport of commit [18e7d7b5](https://github.com/openjdk/jdk/commit/18e7d7b5e710b24e49b995777906a197e35795e6) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

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Commit messages:
 - Backport 18e7d7b5e710b24e49b995777906a197e35795e6

Changes: https://git.openjdk.org/jdk/pull/19888/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19888&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8333716
  Stats: 8 lines in 1 file changed: 6 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/19888.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19888/head:pull/19888

PR: https://git.openjdk.org/jdk/pull/19888