[#3046447] Restore cursor position on #ajax

The tests implemented in this MR are skipped because of #3396536: [random test failure] Re-enable AjaxTest::testAjaxFocus().

The tests can be run locally.

added 180 commits

• f2e8b1d6...23ad40d8 - 179 commits from branch project:11.x
• cc409c73 - Merge branch '11.x' of github.com:drupal/drupal into 3046447-ajax-cursor-position

Compare with previous version