Revert r16112 from trunk.

dart/sdk/lib/_internal/compiler/implementation/lib/core_patch.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.
 
 // Patch file for dart:core classes.
 
 // Patch for 'print' function.
 patch void print(var object) {
   if (object is String) {
     Primitives.printString(object);
@@ skipping 195 matching lines @@
 patch class RegExp {
   patch factory RegExp(String pattern,
                        {bool multiLine: false,
                         bool ignoreCase: false})
     => new JSSyntaxRegExp(pattern,
                           multiLine: multiLine,
                           ignoreCase: ignoreCase);
 }
 
 // Patch for 'identical' function.
-// This is very magical: the compiler knows how to optimize a call to
-// identical, so we can just express identical in terms of itself.
-patch bool identical(Object a, Object b) => identical(a, b);
+patch bool identical(Object a, Object b) {
+  throw new Error('Should not reach the body of identical');
+}