RFR: Merge openjdk/jdk:master [v2]

[William Kemper]

> Merge tag jdk-21+11

William Kemper has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 229 commits:

 - Merge tag 'jdk-21+11' into merge-jdk-21-11
   
   Added tag jdk-21+11 for changeset fcaf8714
 - Merge openjdk/jdk:master
 - Remove unused visualizer option
   
   Reviewed-by: kdnilsen
 - Merge openjdk/jdk:master
   
   Reviewed-by: rkennke
 - Merge openjdk/jdk:master
 - 8299703: GenShen: improvements in card scanning
   
   Reviewed-by: kdnilsen, wkemper
 - Update vestigial comment
   
   Reviewed-by: ysr, kdnilsen
 - Bootstrap old gc should honor aging cycle
   
   Reviewed-by: wkemper
 - Following abbreviated cycle, only increment region age if aging cycle
   
   Reviewed-by: wkemper
 - Fullgc should honor aging cycle
   
   Reviewed-by: wkemper
 - ... and 219 more: https://git.openjdk.org/shenandoah/compare/fcaf8714...9be58b2d

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Changes: https://git.openjdk.org/shenandoah/pull/221/files
 Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=221&range=01
  Stats: 16622 lines in 155 files changed: 15274 ins; 507 del; 841 mod
  Patch: https://git.openjdk.org/shenandoah/pull/221.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah pull/221/head:pull/221

PR: https://git.openjdk.org/shenandoah/pull/221