[jdk21u-dev] RFR: 8317317: G1: Make TestG1RemSetFlags use createTestJvm

[Goetz Lindenmaier]

I backport this to keep the 21u test suite up-to-date. This will simplify future test backports.

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Commit messages:
 - Backport 5bd10521eb5e51e76b20e955addd45f76abba6f7

Changes: https://git.openjdk.org/jdk21u-dev/pull/50/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=50&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317317
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/50.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/50/head:pull/50

PR: https://git.openjdk.org/jdk21u-dev/pull/50