Migrated test block 28 to Dart 2.0.

tests/corelib_strong/string_operations_with_null_test.dart

Index: tests/corelib_strong/string_operations_with_null_test.dart
diff --git a/tests/corelib_strong/string_operations_with_null_test.dart b/tests/corelib_strong/string_operations_with_null_test.dart
deleted file mode 100644
index a05b98592e3afbd87be49b3d4c67b7f3caa15a39..0000000000000000000000000000000000000000
--- a/tests/corelib_strong/string_operations_with_null_test.dart
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright (c) 2013, 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";
-
-@NoInline()
-@AssumeDynamic()
-returnStringOrNull() {
-  return new DateTime.now().millisecondsSinceEpoch == 0 ? 'foo' : null;
-}
-
-main() {
-  Expect.throws(() => 'foo' + returnStringOrNull(), (e) => e is ArgumentError);
-  Expect.throws(() => 'foo'.split(returnStringOrNull()),
-      (e) => e is ArgumentError || e is NoSuchMethodError);
-}