Migrated test block 26 to Dart 2.0.

tests/corelib_2/shuffle_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.
 
 // Dart test for List.shuffle.
 library shuffle_test;
 
 import "dart:typed_data";
 import "dart:math" show Random;
 import "package:expect/expect.dart";
@@ skipping 107 matching lines @@
     index = (index + 1) % _values.length;
     return next;
   }
 
   int nextInt(int limit) => _next % limit;
 
   double nextDouble() => _next / 256.0;
 
   bool nextBool() => _next.isEven;
 }