cleans up sdk patching so we no longer have unresolved names

test/generated_sdk/lib/_internal/compiler/js_lib/native_helper.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of _js_helper;
 
 
 // TODO(ngeoffray): stop using this method once our optimizers can
 // change str1.contains(str2) into str1.indexOf(str2) != -1.
 bool contains(String userAgent, String name) {
@@ skipping 632 matching lines @@
 const _safariHooksTransformer = const JS_CONST(r'''
 function(hooks) { return hooks; }
 ''');
 
 
 const _dartExperimentalFixupGetTagHooksTransformer = const JS_CONST(r'''
 function(hooks) {
   if (typeof dartExperimentalFixupGetTag != "function") return hooks;
   hooks.getTag = dartExperimentalFixupGetTag(hooks.getTag);
 }''');