Add mirrors tests

test/codegen/lib/mirrors/null2_test.dart

Index: test/codegen/lib/mirrors/null2_test.dart
diff --git a/test/codegen/corelib/print_test.dart b/test/codegen/lib/mirrors/null2_test.dart
similarity index 58%
copy from test/codegen/corelib/print_test.dart
copy to test/codegen/lib/mirrors/null2_test.dart
index 7139d75e2f7c498b6317a3c6df52158a186dbdbd..4c5590d398f9ad7f7d251438ffbb1e3f2104c6cc 100644
--- a/test/codegen/corelib/print_test.dart
+++ b/test/codegen/lib/mirrors/null2_test.dart
@@ -2,20 +2,15 @@
 // 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.
 
-import 'package:expect/expect.dart';
+library test.null_test;
 
-class A {
-  toString() {
-    if (false
-          || true  /// 01: runtime error
-        ) {
-      return 499;
-    } else {
-      return "ok";
-    }
-  }
-}
+import 'dart:mirrors';
+
+import 'package:expect/expect.dart';
 
 main() {
-  print(new A());
+  InstanceMirror nullMirror = reflect(null);
+  for (int i = 0; i < 10; i++) {
+    Expect.isTrue(nullMirror.getField(#hashCode).reflectee is int);
+  }
 }