Implement reflect() with Dart code, InstanceMirror.type and ClosureMirror.function with internal co…

runtime/tests/vm/dart/isolate_mirror_local_test.dart

Index: runtime/tests/vm/dart/isolate_mirror_local_test.dart
===================================================================
--- runtime/tests/vm/dart/isolate_mirror_local_test.dart	(revision 25579)
+++ runtime/tests/vm/dart/isolate_mirror_local_test.dart	(working copy)
@@ -390,8 +390,7 @@
 }
 
 void testNullInstanceMirror(InstanceMirror mirror) {
-  // TODO(turnidge): This is returning the wrong class.  Fix it.
-  Expect.equals(const Symbol('Object'), mirror.type.simpleName);
+  Expect.equals(const Symbol('Null'), mirror.type.simpleName);
   Expect.isTrue(mirror.hasReflectee);
   Expect.equals(null, mirror.reflectee);
   Expect.equals("InstanceMirror on null", mirror.toString());