RFR: 8305520: ToggleNotifyJvmtiTest.java fails with release VMs

[Jie Fu]

Add `-XX:+UnlockDiagnosticVMOptions` to fix the failure with release VMs.
Thanks.

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Commit messages:
 - 8305520: ToggleNotifyJvmtiTest.java fails with release VMs

Changes: https://git.openjdk.org/jdk/pull/13318/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13318&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305520
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/13318.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13318/head:pull/13318

PR: https://git.openjdk.org/jdk/pull/13318