Migrated test block 29 to Dart 2.0

tests/corelib/strings_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 testing class 'Strings'.
-
-class StringsTest {
-  StringsTest() {}
-
-  toString() {
-    return "Strings Tester";
-  }
-
-  static testCreation() {
-    String s = "Hello";
-    List<int> l = new List(s.length);
-    for (int i = 0; i < l.length; i++) {
-      l[i] = s.codeUnitAt(i);
-    }
-    String s2 = new String.fromCharCodes(l);
-    Expect.equals(s, s2);
-  }
-
-  static void testMain() {
-    testCreation();
-  }
-}
-
-main() {
-  StringsTest.testMain();
-}