Migrated test block 216 to Dart 2.0.

tests/lib_strong/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);
-  }
-}