MD WebUI: Remove WebUI test focus hack by moving to interactive ui tests

chrome/test/data/webui/cr_elements/cr_action_menu_test.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-/** @fileoverview Tests for cr-action-menu element. */
+/**
+ * @fileoverview Tests for cr-action-menu element. Runs as an interactive UI
+ * test, since many of these tests check focus behavior.
+ */
 suite('CrActionMenu', function() {
   /** @type {?CrActionMenuElement} */
   var menu = null;
 
   /** @type {?NodeList<HTMLElement>} */
   var items = null;
 
   setup(function() {
     PolymerTest.clearBody();
 
@@ skipping 89 matching lines @@
       MockInteractions.keyDownOn(menu, key, [], key);
       assertFalse(menu.open);
     });
   }
 
   test('close on Tab', function() { return testFocusAfterClosing('Tab'); });
   test('close on Escape', function() {
     return testFocusAfterClosing('Escape');
   });
 });