Serialize async marker on getters.

tests/compiler/dart2js/serialization/equivalence_test.dart

 // Copyright (c) 2015, 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 dart2js.serialization_test;
 
 import 'dart:io';
 import '../memory_compiler.dart';
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
@@ skipping 10 matching lines @@
 import 'package:compiler/src/serialization/element_serialization.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/serialization/json_serializer.dart';
 import 'package:compiler/src/serialization/serialization.dart';
 import 'package:expect/expect.dart';
 import 'test_helper.dart';
 
 const TEST_SOURCES = const <String, String>{
   'main.dart': '''
 import 'a.dart' deferred as a;
+
+asyncMethod() async {}
+asyncStarMethod() async* {}
+syncStarMethod() sync* {}
+get asyncGetter async {}
+get asyncStarGetter async* {}
+get syncStarGetter sync* {}
+
 ''',
   'a.dart': '''
 ''',
 };
 
 main(List<String> arguments) {
   // Ensure that we can print out constant expressions.
   DEBUG_MODE = true;
 
   Uri entryPoint;
@@ skipping 772 matching lines @@
     checkElementIdentities(
         element1, element2, 'deferredImport',
         element1.deferredImport, element2.deferredImport);
     if (element1.isDeferred) {
       checkElementProperties(element1, element2,
           'loadLibrary', element1.loadLibrary, element2.loadLibrary);
     }
     // TODO(johnniwinther): Check members.
   }
 }