Migrated test block 19 to Dart 2.0.

tests/corelib/reg_exp_group_test.dart

-// 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.
-
-import "package:expect/expect.dart";
-
-// Dart test program for RegExp.group.
-
-class RegExpGroupTest {
-  static testMain() {
-    var match = new RegExp("(a(b)((c|de)+))").firstMatch("abcde");
-    Expect.equals('abcde', match.group(0));
-    Expect.equals('abcde', match.group(1));
-    Expect.equals('b', match.group(2));
-    Expect.equals('cde', match[3]);
-    Expect.equals('de', match[4]);
-  }
-}
-
-main() {
-  RegExpGroupTest.testMain();
-}