RFR: 8348430: Update jfr tests to allow execution with different vm flags

[Erik Gahlin]

Could I have review of a change that allows some tests to run with flags.

Thanks
Erik

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Commit messages:
 - Initial

Changes: https://git.openjdk.org/jdk/pull/23369/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23369&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348430
  Stats: 10 lines in 10 files changed: 0 ins; 10 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23369.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23369/head:pull/23369

PR: https://git.openjdk.org/jdk/pull/23369