Revert "Remove Expect from core library."

tests/lib/math/random_test.dart

 // Copyright (c) 2013, 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 a coin toss with Random.nextBool() is fair.
 
 // Library tag to allow Dartium to run the test.
 library random_test;
 
-import "package:expect/expect.dart";
 import 'dart:math';
 
 main() {
   var rnd = new Random(20130307);
   // Make sure we do not break the random number generation.
   var i = 0;
   Expect.equals(         0, rnd.nextInt(1 << ++i));
   Expect.equals(         2, rnd.nextInt(1 << ++i));
   Expect.equals(         7, rnd.nextInt(1 << ++i));
   Expect.equals(         8, rnd.nextInt(1 << ++i));
@@ skipping 22 matching lines @@
   Expect.equals(  80223657, rnd.nextInt(1 << ++i));
   Expect.equals( 142194155, rnd.nextInt(1 << ++i));
   Expect.equals(  31792146, rnd.nextInt(1 << ++i));
   Expect.equals(1042196170, rnd.nextInt(1 << ++i));
   Expect.equals(1589656273, rnd.nextInt(1 << ++i));
   Expect.equals(1547294578, rnd.nextInt(1 << ++i));
   Expect.equals(32, i);
   // If max is too large expect an ArgumentError. 
   Expect.throws(() => rnd.nextInt((1 << i)+1), (e) => e is ArgumentError);
 }