RFR: Remove perf event modifiers to validate if they are supported

[Galder Zamarreño]

Fixes https://bugs.openjdk.org/browse/CODETOOLS-7903740

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Commit messages:
 - Remove perf event modifiers to validate if they are supported

Changes: https://git.openjdk.org/jmh/pull/132/files
  Webrev: https://webrevs.openjdk.org/?repo=jmh&pr=132&range=00
  Stats: 8 lines in 1 file changed: 7 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jmh/pull/132.diff
  Fetch: git fetch https://git.openjdk.org/jmh.git pull/132/head:pull/132

PR: https://git.openjdk.org/jmh/pull/132