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

[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

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

Depends on: https://git.openjdk.org/jdk/pull/26670

Commit messages:
 - 8365034

Changes: https://git.openjdk.org/jdk/pull/26674/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26674&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365034
  Stats: 5 lines in 1 file changed: 1 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