RFR: 8365034: G1: Remove num_groups_selected in G1CollectionSet::select_candidates_from_optional_groups as it is unnecessary [v2]

[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 incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - * ayang review
 - Merge branch '8364934-g1collectionset-renaming' into 8365034-remove-unnecessary-num_selected_regions
 - 8365034
   
   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

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26674/files
  - new: https://git.openjdk.org/jdk/pull/26674/files/60a9aec4..82287099

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26674&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26674&range=00-01

  Stats: 26600 lines in 855 files changed: 14971 ins; 8263 del; 3366 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