RFR: 8279333: Some JFR tests do not accept 'GCLocker Initiated GC' as a valid GC cause

[Fairoz Matte]

Some JFR tests do not accept 'GCLocker Initiated GC' as a valid GC cause

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Commit messages:
 - 8279333: Some JFR tests do not accept 'GCLocker Initiated GC' as a valid GC cause

Changes: https://git.openjdk.java.net/jdk/pull/6978/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6978&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8279333
  Stats: 4 lines in 2 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6978.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6978/head:pull/6978

PR: https://git.openjdk.java.net/jdk/pull/6978