Migrate block 116.

tests/language_strong/if_null_evaluation_order_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.
-
-// Evaluation of an if-null expression e of the form e1 ?? e2 is equivalent to
-// the evaluation of the expression ((x) => x == null ? e2 : x)(e1).
-//
-// Therefore, e1 should be evaluated first; if it is non-null, e2 should not
-// be evaluated.
-
-import "package:expect/expect.dart";
-
-void bad() {
-  throw new Exception();
-}
-
-bool firstExecuted = false;
-
-first() {
-  firstExecuted = true;
-  return null;
-}
-
-second() {
-  Expect.isTrue(firstExecuted);
-  return 2;
-}
-
-main() {
-  // Make sure the "none" test fails if "??" is not implemented.  This makes
-  // status files easier to maintain.
-  var _ = null ?? null;
-
-  Expect.equals(1, 1 ?? bad()); //# 01: ok
-  Expect.equals(2, first() ?? second()); //# 02: ok
-}