Revert "Remove Expect from core library."

tests/isolate/port_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.
 
 // Test properties of ports.
 // Note: unittest.dart depends on ports, in particular on the behaviour tested
 // here. To keep things simple, we don't use the unittest library here.
 
 library PortTest;
-import "package:expect/expect.dart";
 import 'dart:isolate';
 import '../../pkg/unittest/lib/matcher.dart';
 
 main() {
   testHashCode();
   testEquals();
   testMap();
 }
 
 void testHashCode() {
@@ skipping 32 matching lines @@
   Expect.isFalse(map.containsKey(rp0.toSendPort()));
   Expect.equals(map[rp1.toSendPort()], 87);
 
   map.remove(rp1.toSendPort());
   Expect.isFalse(map.containsKey(rp0.toSendPort()));
   Expect.isFalse(map.containsKey(rp1.toSendPort()));
 
   rp0.close();
   rp1.close();
 }