RFR: 8349213: G1: Clearing bitmaps during collection set merging not claimed by region

[Thomas Schatzl]

Hi all,

  please review this change that makes (optional) bitmap clearing during merging remembered sets claim regions. Otherwise every thread will do the (currently little) work themselves over and over again.

Testing: tier1-3

Thanks,
  Thomas

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

Commit messages:
 - * move commenty
 - 8349213: G1: Clearing bitmaps during collection set merging not claimed by region

Changes: https://git.openjdk.org/jdk/pull/23419/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23419&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349213
  Stats: 30 lines in 1 file changed: 8 ins; 20 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/23419.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23419/head:pull/23419

PR: https://git.openjdk.org/jdk/pull/23419