Migrated test block 28 to Dart 2.0.

tests/corelib_2/string_replace_dollar_test.dart

 // Copyright (c) 2012, 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";
 
 main() {
   String jsText = r"""'$'
 """;
   String htmlStr = '%%DART';
   String htmlOut = htmlStr.replaceAll("%%DART", jsText);
   Expect.equals(jsText, htmlOut);
   htmlOut = htmlStr.replaceFirst("%%DART", jsText);
   Expect.equals(jsText, htmlOut);
   htmlOut = htmlStr.replaceAll(new RegExp("%%DART"), jsText);
   Expect.equals(jsText, htmlOut);
   htmlOut = htmlStr.replaceFirst(new RegExp("%%DART"), jsText);
   Expect.equals(jsText, htmlOut);
 
   // Regression test, http://dartbug.com/17886
   String doubleDollar = r"$'$`";
   var string = r"flip-flip-flop";
   var result = string.replaceFirst("flip", doubleDollar);
   Expect.equals(r"$'$`-flip-flop", result);
   result = string.replaceAll("flip", doubleDollar);
   Expect.equals(r"$'$`-$'$`-flop", result);
 }