(cherry picked from commit 714c3414196f3fab7ae451b79cd30ff041e38366)

Issue #3252214 by Spokje: Move tests for integrations between QuickEdit and CKEditor5 into QuickEdit so that it can more easily be moved into contrib

(cherry picked from commit f94b1247)

Issue #2886615 by scott_euser, clemens.tolboom, quietone, joachim, alexpott, Lendude: comment_empty_title_test has invalid hook

(cherry picked from commit d7082acf)

move tests  cases that don't work when extended by other test files to a separate test that is not extended

Issue #3239500 by hooroomoo, bnjmnm, lauriii: Add Array.includes polyfill to support IE11 and Opera Mini

(cherry picked from commit b615dbd2)

(cherry picked from commit 86e9f19a)

Issue #2871357 by alexpott, kriboogh: Installer tasks using multiple batch sets in non-interactive mode do not get executed

(cherry picked from commit 18916c48)