Migrate block 39 language/async_backwards ... /async_star_take.

tests/language_2/async_or_generator_return_type_stacktrace_test.dart

Index: tests/language_2/async_or_generator_return_type_stacktrace_test.dart
diff --git a/tests/language_2/async_or_generator_return_type_stacktrace_test.dart b/tests/language_2/async_or_generator_return_type_stacktrace_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..612cf8b3225469865a30150c9413cfb6388495fe
--- /dev/null
+++ b/tests/language_2/async_or_generator_return_type_stacktrace_test.dart
@@ -0,0 +1,11 @@
+// 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";
+
+void badReturnTypeAsync() async {} // //# 01: compile-time error
+void badReturnTypeAsyncStar() async* {} // //# 02: compile-time error
+void badReturnTypeSyncStar() sync* {} // //# 03: compile-time error
+
+void main() {}