Migrate language/arithmetic2_test ... language/async_await_syntax_test.

tests/language_strong/assign_top_method_test.dart

Index: tests/language_strong/assign_top_method_test.dart
diff --git a/tests/language_strong/assign_top_method_test.dart b/tests/language_strong/assign_top_method_test.dart
deleted file mode 100644
index 137943b8f4e1f794777e617b60b71cc6a4e2d5f6..0000000000000000000000000000000000000000
--- a/tests/language_strong/assign_top_method_test.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright (c) 2012, 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";
-
-method() {
-  return 0;
-}
-
-main() {
-  // Illegal, can't change a top level method
-  Expect.throws(() { method = () { return 1; }; }, //# 01: static type warning
-                (e) => e is NoSuchMethodError); //   //# 01: continued
-}