Migrated test block 168 to Dart 2.0.

tests/lib_strong/async/future_or_only_in_async_test.dart

Index: tests/lib_strong/async/future_or_only_in_async_test.dart
diff --git a/tests/lib_strong/async/future_or_only_in_async_test.dart b/tests/lib_strong/async/future_or_only_in_async_test.dart
deleted file mode 100644
index c8fb8a5d9080e7269cb6bc026f099e0c6b0cad02..0000000000000000000000000000000000000000
--- a/tests/lib_strong/async/future_or_only_in_async_test.dart
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright (c) 2016, 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.
-
-// `FutureOr<T>` is only visible when `dart:async` is imported.
-
-dynamic foo(dynamic x) {
-  return x as
-      FutureOr< // //# 00: runtime error, static type warning
-          int
-      > //         //# 00: continued
-      ;
-}
-
-main() {
-  if (499 != foo(499)) throw "bad";
-}