Disable flaky MD Settings tests.

chrome/browser/ui/webui/settings/settings_basic_browsertest.js

 // Copyright 2015 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.
 
 /**
  * @extends {testing.Test}
  * @constructor
  */
 function SettingsBasicBrowserTest() {}
 
 SettingsBasicBrowserTest.prototype = {
   __proto__: testing.Test.prototype,
 
   /** @override */
   browsePreload: 'chrome://md-settings/',
 
   /**
    * TODO(dpapad): Fix accessibility issues and enable checks.
    * @override
    */
   runAccessibilityChecks: false,
 };
 
-TEST_F('SettingsBasicBrowserTest', 'NoConsoleErrors', function() {
+// Flaky timeout failures on Linux Tests (dbg) and Win7 Tests (dbg); see
+// https://crbug.com/558434.
+TEST_F('SettingsBasicBrowserTest', 'DISABLED_NoConsoleErrors', function() {
   assertEquals(this.browsePreload, document.location.href);
   // Nothing else to assert here. If there are errors in the console the test
   // will automatically fail.
 });