RFR: 8339695: GenShen: Concurrent reset performance has regressed

[William Kemper]

Clean

-------------

Commit messages:
 - Backport 08c64116f1b604b5e0d3e777b83636753282b435

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/101/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=101&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339695
  Stats: 34 lines in 1 file changed: 6 ins; 6 del; 22 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/101.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/101/head:pull/101

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/101