Migrated test block 216 to Dart 2.0.

tests/lib_2/math/random_big_test.dart

 // Copyright (c) 2014, 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.
 
 // Test that Random can deal with a seed outside 64-bit range.
 
 // Library tag to allow Dartium to run the test.
 library random_big;
 
 import "package:expect/expect.dart";
 import 'dart:math';
 
 main() {
   var results = [];
   for (var i = 60; i < 80; i++) {
     var rng = new Random(1 << i);
     var val = rng.nextInt(100000);
     print("$i: $val");
     Expect.isFalse(results.contains(val));
     results.add(val);
   }
 }