RFR: 8331015: Obsolete -XX:+UseNotificationThread

[Alex Menkov]

Obsolete UseNotificationThread flag which was deprecated in JDK 23.

Testing: tier1..tier5

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Commit messages:
 - fix

Changes: https://git.openjdk.org/jdk/pull/20381/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20381&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331015
  Stats: 41 lines in 7 files changed: 1 ins; 31 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/20381.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20381/head:pull/20381

PR: https://git.openjdk.org/jdk/pull/20381