RFR: 8162: Update OptionsCheckRule to JDK21

[Henrik Dafgård]

Brings the OptionsCheckRule up to date with the state of JVM flags as of JDK 21.

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Commit messages:
 - Update OptionsCheckRule to JDK 21

Changes: https://git.openjdk.org/jmc/pull/542/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=542&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8162
  Stats: 47 lines in 2 files changed: 45 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jmc/pull/542.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/542/head:pull/542

PR: https://git.openjdk.org/jmc/pull/542