Tests: Skip a problematic keyboard test in IE with jQuery 3.6

jQuery 3.6 has issues with focus handling in IE which breaks this test.
The issues were fixed in jQuery 3.7, so we just accept them here.

Closes gh-2231

tests/unit/tabs/core.js

@@ -180,7 +180,13 @@ QUnit.test( "accessibility - ajax", function( assert ) {
 	} );
 } );
 
-QUnit.test( "keyboard support - LEFT, RIGHT, UP, DOWN, HOME, END, SPACE, ENTER", function( assert ) {
+QUnit[
+
+	// Support: IE 11+, jQuery 3.6 only
+	// jQuery 3.6 has issues with focus handling in IE which breaks this test.
+	// The issues were fixed in jQuery 3.7, so we just accept them here.
+	jQuery.fn.jquery.indexOf( "3.6." ) === 0 && document.documentMode ? "skip" : "test"
+]( "keyboard support - LEFT, RIGHT, UP, DOWN, HOME, END, SPACE, ENTER", function( assert ) {
 	var ready = assert.async();
 	assert.expect( 92 );
 	var element = $( "#tabs1" ).tabs( {