Fix equality of implicit closures in the Dart VM.

runtime/lib/function_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 class Function {
   static _apply(List arguments, List names)
       native "Function_apply";
 
   /* patch */ static apply(Function function,
                            List positionalArguments,
@@ skipping 10 matching lines @@
     int nameIndex = 0;
     if (numNamedArguments > 0) {
       namedArguments.forEach((name, value) {
         arguments[argumentIndex++] = value;
         names[nameIndex++] = _collection_dev.Symbol.getName(name);
       });
     }
     return _apply(arguments, names);
   }
 }
+
+bool _Closure_comparison(var a, var b) native "Closure_comparison";
+
+int _Closure_hashCode(var a) native "Closure_hashCode";