Migrate language/async_backwards... ... language/async_star_take...

tests/language/async_finally_rethrow_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.
-
-import "dart:async";
-import "package:expect/expect.dart";
-
-foo() async {
-  try {
-    await 1;
-    throw "error";
-  } on String catch (e) {
-    await 2;
-    throw e;
-  } finally {
-    await 3;
-  }
-}
-
-main() async {
-  var error = "no error";
-  try {
-    await foo();
-  } catch (e) {
-    error = e;
-  }
-  Expect.equals("error", error);
-}