Issue #3278625 by catch, Taran2L: Remove jquery.tabbable.shim

core/core.libraries.yml

core/misc/jquery.tabbable.shim.js

...ontroller/TabbableShimDialogIntegrationTestController.php

...e_shim_test/src/Controller/TabbableShimTestController.php

...ts/modules/tabbable_shim_test/tabbable_shim_test.info.yml

...modules/tabbable_shim_test/tabbable_shim_test.routing.yml

core/tests/Drupal/Nightwatch/Tests/tabbableShimTest.js