Revert "Remove Expect from core library."

tests/language/typed_message_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.
 // Dart test program for testing isolate communication with
 // typed objects.
 // VMOptions=--checked
 
 library TypedMessageTest;
-import "package:expect/expect.dart";
 import "dart:isolate";
 
 void logMessages() {
   print("Starting log server.");
   port.receive((List<int> message, SendPort replyTo) {
     print("Log $message");
     Expect.equals(5, message.length);
     Expect.equals(0, message[0]);
     Expect.equals(1, message[1]);
     Expect.equals(2, message[2]);
     Expect.equals(3, message[3]);
     Expect.equals(4, message[4]);
     port.close();
     replyTo.send(1, null);
     print("Stopping log server.");
   });
 }
 
 main() {
   SendPort remote = spawnFunction(logMessages);
   List<int> msg = new List<int>(5);
   for (int i = 0; i < 5; i++) {
     msg[i] = i;
   }
   remote.call(msg).then((int message) {
     Expect.equals(1, message);
   });
 }