RFR: 8365034: G1: Remove num_groups_selected in G1CollectionSet::select_candidates_from_optional_groups as it is unnecessary [v4]

[Thomas Schatzl]

> Hi all,
> 
>   please review this removal of the local `num_selected_regions` from `G1CollectionSet::select_candidates_from_optional_groups()` - the same information is maintained within the local `selected_groups` list.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 14 commits:

 - * remove unwanted chagnes
 - Merge branch 'master' into 8365034-remove-unnecessary-num_selected_regions
 - Merge branch 'master' into 8365034-remove-unnecessary-num_selected_regions
 - * ayang review
 - Merge branch '8364934-g1collectionset-renaming' into 8365034-remove-unnecessary-num_selected_regions
 - Merge branch 'master' into 8364934-g1collectionset-renaming
 - Merge branch 'master' into 8364934-g1collectionset-renaming
 - * one more renaming: prepare_groups_for_scan() -> prepare_for_scan()
 - Merge branch '8364925-improve-program-flow-inc-cset' into 8364934-g1collectionset-renaming
 - * ayang review
 - ... and 4 more: https://git.openjdk.org/jdk/compare/e1c58f85...b9a66b12

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Changes: https://git.openjdk.org/jdk/pull/26674/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26674&range=03
  Stats: 4 lines in 1 file changed: 0 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26674.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26674/head:pull/26674

PR: https://git.openjdk.org/jdk/pull/26674