Add @MirrorsUsed annotations to speed up tests.

tests/lib/mirrors/invoke_named_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // 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 test.invoke_named_test;
 
+@MirrorsUsed(targets: "test.invoke_named_test")
 import 'dart:mirrors';
 
 import 'dart:async' show Future;
 
 import 'package:expect/expect.dart';
 import 'invoke_test.dart';
 
 // TODO(ahe): Remove this variable (http://dartbug.com/12863).
 bool isDart2js = false;
 
@@ skipping 271 matching lines @@
   if (isDart2js) return;
 
   testSyncInvoke(reflectClass(D)); // ClassMirror
   LibraryMirror lib = reflectClass(D).owner;
   testSyncInvoke(lib); // LibraryMirror
 
   testSyncNewInstance();
 
   testSyncApply();
 }