Validate that (actual) resynthesized elements have the same runtimeType as originals.

pkg/analyzer/lib/src/generated/testing/element_factory.dart

Index: pkg/analyzer/lib/src/generated/testing/element_factory.dart
diff --git a/pkg/analyzer/lib/src/generated/testing/element_factory.dart b/pkg/analyzer/lib/src/generated/testing/element_factory.dart
index 72d8acff08648a7ba3b61ef71ef25e88aa69fbe9..7ea7a3a4f173bf892a315a578244fa42aef33e76 100644
--- a/pkg/analyzer/lib/src/generated/testing/element_factory.dart
+++ b/pkg/analyzer/lib/src/generated/testing/element_factory.dart
@@ -202,7 +202,8 @@ class ElementFactory {
   }
 
   static FieldElementImpl fieldElement(
-      String name, bool isStatic, bool isFinal, bool isConst, DartType type) {
+      String name, bool isStatic, bool isFinal, bool isConst, DartType type,
+      {Expression initializer}) {
     FieldElementImpl field = isConst
         ? new ConstFieldElementImpl(name, 0)
         : new FieldElementImpl(name, 0);
@@ -210,6 +211,9 @@ class ElementFactory {
     field.final2 = isFinal;
     field.static = isStatic;
     field.type = type;
+    if (isConst) {
+      (field as ConstFieldElementImpl).constantInitializer = initializer;
+    }
     PropertyAccessorElementImpl getter =
         new PropertyAccessorElementImpl.forVariable(field);
     getter.getter = true;
@@ -496,6 +500,16 @@ class ElementFactory {
     return parameter;
   }
 
+  static ParameterElementImpl namedParameter3(String name,
+      {DartType type, Expression initializer}) {
+    DefaultParameterElementImpl parameter =
+        new DefaultParameterElementImpl(name, 0);
+    parameter.parameterKind = ParameterKind.NAMED;
+    parameter.type = type;
+    parameter.constantInitializer = initializer;
+    return parameter;
+  }
+
   static ParameterElementImpl positionalParameter(String name) {
     ParameterElementImpl parameter = new ParameterElementImpl(name, 0);
     parameter.parameterKind = ParameterKind.POSITIONAL;