Add mirrors tests

test/codegen/lib/mirrors/empty_test.dart

Index: test/codegen/lib/mirrors/empty_test.dart
diff --git a/test/codegen/language/enum_is_keyword_test.dart b/test/codegen/lib/mirrors/empty_test.dart
similarity index 60%
copy from test/codegen/language/enum_is_keyword_test.dart
copy to test/codegen/lib/mirrors/empty_test.dart
index 2d24d94810ab6c41b7cc44c42d7a98d5116df763..506cdfbef3af725e005a3841000c65a9441b2f76 100644
--- a/test/codegen/language/enum_is_keyword_test.dart
+++ b/test/codegen/lib/mirrors/empty_test.dart
@@ -2,9 +2,10 @@
 // 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.
 
-// Test that `enum` is considered a keyword and therefore invalid as the name of
-// declarations.
+import 'dart:mirrors';
+import 'empty.dart';
 
 main() {
-  var enum; /// 01: compile-time error
+  var empty = currentMirrorSystem().findLibrary(#empty);
+  print(empty.location);  // Used to crash VM.
 }