RFR: 8331048: G1: Prune rebuild candidates based on G1HeapWastePercent early

[Ivan Walulya]

Hi, 

Please review this change that moves the `G1CollectionSetChooser::build` out of the cleanup pause into the remark pause. This prunes the rebuild candidates based on G1HeapWastePercent, thereby reducing the rebuild time in cases where pruning happens. 

Testing: Tier 1 - 5

![concurrent_rebuild](https://github.com/openjdk/jdk/assets/69453999/b14dd9d7-24e7-43ed-bf0f-5d3030d9180f)

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Commit messages:
 - remove methods
 - Merge branch 'master' into PruneBeforeRebuild
 - remove Fixme
 - cleanup
 - Merge branch 'master' into GroupOldRegions_Remsets
 - save
 - clean up
 - save

Changes: https://git.openjdk.org/jdk/pull/18970/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18970&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331048
  Stats: 12 lines in 4 files changed: 8 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18970.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18970/head:pull/18970

PR: https://git.openjdk.org/jdk/pull/18970