Revert "Wat if you closure identical?"

runtime/lib/identical_patch.dart

Index: runtime/lib/identical_patch.dart
diff --git a/runtime/lib/identical_patch.dart b/runtime/lib/identical_patch.dart
index 3ea32de44c009aed1ff944fbc4f363a7a1e17b77..218b3c83f1b46bb2988ee1f2b6f4b3185072ec17 100644
--- a/runtime/lib/identical_patch.dart
+++ b/runtime/lib/identical_patch.dart
@@ -2,4 +2,6 @@
 // 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 bool identical(Object a, Object b) => a === b;
+patch bool identical(Object a, Object b) {
+  throw new Error('Should not reach the body of identical');  
+}