Add output_type_test

tests/compiler/dart2js/data/deferred_helper.dart

Index: tests/compiler/dart2js/data/deferred_helper.dart
diff --git a/tests/compiler/dart2js/data/deferred_helper.dart b/tests/compiler/dart2js/data/deferred_helper.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9df96abae7fa2f589cd3c8395cfc3228e4ea4e20
--- /dev/null
+++ b/tests/compiler/dart2js/data/deferred_helper.dart
@@ -0,0 +1,10 @@
+// Copyright (c) 2017, 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 'deferred_lib.dart' deferred as lib;
+
+main() async {
+  await lib.loadLibrary();
+  print(new lib.Class().method());
+}