RFR: 8364423: G1: Refactor G1UpdateRegionLivenessAndSelectForRebuildTask [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this refactoring of `G1UpdateRegionLivenessAndSelectForRebuildTask` to remove some code duplication, which makes it simpler to add more common code
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  * undo factoring out common code when preparing for rebuild.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26574/files
  - new: https://git.openjdk.org/jdk/pull/26574/files/0704afba..90aa50dd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26574&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26574&range=00-01

  Stats: 19 lines in 1 file changed: 7 ins; 7 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/26574.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26574/head:pull/26574

PR: https://git.openjdk.org/jdk/pull/26574