Migrating a block of dart 1 tests to dart 2

tests/language/class_syntax2_test.dart

-// 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.
-
-// Regression test for dart2js bug http://dartbug.com/11570.
-
-import 'package:expect/expect.dart';
-
-void main() {
-  var c = new Cool(true);
-  Expect.stringEquals('{}', '${c.thing}');
-
-  c = new Cool(false);
-  Expect.stringEquals('[]', '${c.thing}');
-
-  c = new Cool.alt(true);
-  Expect.stringEquals('{}', '${c.thing}');
-
-  c = new Cool.alt(false);
-  Expect.stringEquals('[]', '${c.thing}');
-}
-
-class Cool {
-  final thing;
-
-  Cool(bool option) : thing = option ? <String, String>{} : <String>[];
-  Cool.alt(bool option) : thing = !option ? <String>[] : <String, String>{};
-}