Add mirrors tests

test/codegen/lib/mirrors/library_metatarget_test_annotations_lib.dart

Index: test/codegen/lib/mirrors/library_metatarget_test_annotations_lib.dart
diff --git a/test/codegen/language/compiler_annotations.dart b/test/codegen/lib/mirrors/library_metatarget_test_annotations_lib.dart
similarity index 50%
copy from test/codegen/language/compiler_annotations.dart
copy to test/codegen/lib/mirrors/library_metatarget_test_annotations_lib.dart
index c920add403b030de5e012117306b265733e869b8..20fcfcf1017fb0a4d335623fb8174cd866aca8db 100644
--- a/test/codegen/language/compiler_annotations.dart
+++ b/test/codegen/lib/mirrors/library_metatarget_test_annotations_lib.dart
@@ -2,11 +2,16 @@
 // 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.
 
-library compiler_annotations;
+// Regression test for the combined use of metatargets and library tags.
 
-// This library contains annotations useful for testing.
+library annotations;
 
-// TODO(ngeoffray): Implement in dart2js.
-class DontInline {
-  const DontInline();
+class UsedOnlyOnLibrary {
+  const UsedOnlyOnLibrary();
 }
+const usedOnlyOnLibrary = const UsedOnlyOnLibrary();
+
+class Reflectable {
+  const Reflectable();
+}
+const Reflectable reflectable = const Reflectable();