fixes #221, initial sync*, async, async* implementation

test/codegen/syncstar_syntax.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.
 
+import 'package:expect/expect.dart';
+
 Iterable<int> foo() sync* {
   yield 1;
   yield* [2, 3];
 }
 
 class Class {
   Iterable<int> bar() sync* {
     yield 1;
     yield* [2, 3];
   }
 
   static Iterable<int> baz() sync* {
     yield 1;
     yield* [2, 3];
   }
 }
 
 main() {
   Iterable<int> qux() sync* {
     yield 1;
     yield* [2, 3];
   }
 
-  foo().forEach(print);
-  new Class().bar().forEach(print);
-  Class.baz().forEach(print);
-  qux().forEach(print);
+  Expect.listEquals([1, 2, 3], foo().toList());
+  Expect.listEquals([1, 2, 3], new Class().bar().toList());
+  Expect.listEquals([1, 2, 3], Class.baz().toList());
+  Expect.listEquals([1, 2, 3], qux().toList());
 }