Serialize ParameterElement.node and ParameterElement.initializer for type inference

tests/compiler/dart2js/serialization/test_helper.dart

Index: tests/compiler/dart2js/serialization/test_helper.dart
diff --git a/tests/compiler/dart2js/serialization/test_helper.dart b/tests/compiler/dart2js/serialization/test_helper.dart
index 1a05c98a801799d9c3272e545d4f732aaec4cc28..d753b53a4c0f09d246eb52a733cee0b44eb31e4c 100644
--- a/tests/compiler/dart2js/serialization/test_helper.dart
+++ b/tests/compiler/dart2js/serialization/test_helper.dart
@@ -21,7 +21,7 @@ import 'package:compiler/src/serialization/element_serialization.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/serialization/json_serializer.dart';
 import 'package:compiler/src/serialization/serialization.dart';
-
+import 'package:compiler/src/tree/nodes.dart';
 
 /// Strategy for checking equivalence.
 ///
@@ -97,6 +97,13 @@ class CheckStrategy implements TestStrategy {
       List<ConstantExpression> list2) {
     return checkConstantLists(object1, object2, property, list1, list2);
   }
+
+  @override
+  bool testNodes(Object object1, Object object2, String property,
+      Node node1, Node node2) {
+    return new NodeEquivalenceVisitor(this).testNodes(
+        object1, object2, property, node1, node2);
+  }
 }
 
 /// Check that the values [property] of [object1] and [object2], [value1] and