[8.19] Threadpool merge executor does not block aborted merges (#129613)#129728

elasticsearchmachine merged 4 commits intoelastic:8.19elastic/elasticsearch:8.19from

albertzaharovits:backport-819-consider-aborting-merges-while-enqueuedalbertzaharovits/elasticsearch:backport-819-consider-aborting-merges-while-enqueuedCopy head branch name to clipboard