Revert "Remove Expect from core library."

tests/isolate/serialization_test.dart

 // Copyright (c) 2011, 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 serialization of messages without spawning
 // isolates.
 
 // ---------------------------------------------------------------------------
 // Serialization test.
 // ---------------------------------------------------------------------------
 library SerializationTest;
-import "package:expect/expect.dart";
 import 'dart:isolate';
 
 main() {
   // TODO(sigmund): fix once we can disable privacy for testing (bug #1882)
   testAllTypes(TestingOnly.copy);
   testAllTypes(TestingOnly.serialize);
 }
 
 void testAllTypes(Function f) {
   copyAndVerify(0, f);
@@ skipping 46 matching lines @@
     Expect.isTrue(copy is Map);
     Expect.equals(o.length, copy.length);
     o.forEach((key, value) {
       Expect.isTrue(copy.containsKey(key));
       verify(value, copy[key]);
     });
   } else {
     Expect.fail("Unexpected object encountered");
   }
 }