Add @MirrorsUsed annotations to speed up tests.

tests/lib/mirrors/fake_function_without_call_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 lib;
+
+@MirrorsUsed(targets: "lib")
 import "dart:mirrors";
 
 import "package:expect/expect.dart";
 
 class MultiArityFunction implements Function {
   noSuchMethod(Invocation msg) {
     if (msg.memberName != #call) return super.noSuchMethod(msg);
     return msg.positionalArguments.join(",");
   }
 }
@@ skipping 16 matching lines @@
   Expect.equals('a', cm.apply(['a']).reflectee);
   Expect.equals('a,b', cm.apply(['a', 'b']).reflectee);
   Expect.equals('a,b,c', cm.apply(['a', 'b', 'c']).reflectee);
 
   MethodMirror mm = cm.function;
   Expect.isNull(mm);
 
   ClassMirror km = cm.type;
   Expect.equals(reflectClass(MultiArityFunction), km);
 }