Migrate the language tests up to arithmetic_test.

tests/language_strong/ackermann_test.dart

Index: tests/language_strong/ackermann_test.dart
diff --git a/tests/language_strong/ackermann_test.dart b/tests/language_strong/ackermann_test.dart
deleted file mode 100644
index 87cadeb88a1a69e3ec4c53e4cdc8f4e0c8b92943..0000000000000000000000000000000000000000
--- a/tests/language_strong/ackermann_test.dart
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright (c) 2011, 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.
-// Dart version of two-argument Ackermann-Peter function.
-
-import "package:expect/expect.dart";
-
-class AckermannTest {
-  static ack(m, n) {
-    return m == 0
-        ? n + 1
-        : ((n == 0) ? ack(m - 1, 1) : ack(m - 1, ack(m, n - 1)));
-  }
-
-  static testMain() {
-    Expect.equals(253, ack(3, 5));
-  }
-}
-
-main() {
-  AckermannTest.testMain();
-}