Add equivalence check of NativeData and InterceptorData

tests/compiler/dart2js/serialization/test_helper.dart

 // Copyright (c) 2016, 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.
 
 library dart2js.serialization_test_helper;
 
 import 'dart:collection';
 import 'package:compiler/src/common/resolution.dart';
 import 'package:compiler/src/constants/expressions.dart';
 import 'package:compiler/src/constants/values.dart';
@@ skipping 210 matching lines @@
     throw message;
   }
   return true;
 }
 
 /// Check equivalence of the two iterables, [set1] and [set1], as sets using
 /// [elementEquivalence] to compute the pair-wise equivalence.
 ///
 /// Uses [object1], [object2] and [property] to provide context for failures.
 bool checkMapEquivalence(var object1, var object2, String property, Map map1,
-    Map map2, bool sameKey(a, b), bool sameValue(a, b)) {
+    Map map2, bool sameKey(a, b), bool sameValue(a, b),
+    {bool allowExtra: false}) {
   List<List> common = <List>[];
   List unfound = [];
-  Set remaining = computeSetDifference(map1.keys, map2.keys, common, unfound,
+  Set extra = computeSetDifference(map1.keys, map2.keys, common, unfound,
       sameElement: sameKey);
-  if (unfound.isNotEmpty || remaining.isNotEmpty) {
+  if (unfound.isNotEmpty || (!allowExtra && extra.isNotEmpty)) {
     String message =
         "Map key mismatch for `$property` on $object1 vs $object2: \n"
         "Common:\n ${common.join('\n ')}\n"
         "Unfound:\n ${unfound.join('\n ')}\n"
-        "Extra: \n ${remaining.join('\n ')}";
+        "Extra: \n ${extra.join('\n ')}";
     throw message;
   }
   for (List pair in common) {
     check(pair[0], pair[1], 'Map value for `$property`', map1[pair[0]],
         map2[pair[1]], sameValue);
   }
   return true;
 }
 
 /// Checks the equivalence of the identity (but not properties) of [element1]
@@ skipping 557 matching lines @@
               strategy.testTypeLists(a, b, 'namedParameterTypes',
                   aType.namedParameterTypes, b.namedParameterTypes);
         }
         return false;
       default:
         throw new UnsupportedError('Unsupported equivalence: '
             '$a (${a.runtimeType}) vs $b (${b.runtimeType})');
     }
   }
 }