[jdk21u-dev] RFR: 8362532: Test gc/g1/plab/* duplicate command-line options

[Goetz Lindenmaier]

I backport this for parity with 21.0.10-oracle.

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Commit messages:
 - Backport 13bab09bffc411dde324599c2e15852ef4b53d55

Changes: https://git.openjdk.org/jdk21u-dev/pull/2242/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2242&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8362532
  Stats: 9 lines in 2 files changed: 0 ins; 3 del; 6 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2242.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2242/head:pull/2242

PR: https://git.openjdk.org/jdk21u-dev/pull/2242