Remove Expect from core library.

tests/standalone/int_array_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 native int arrays.
 
 // Library tag to be able to run in html test framework.
 library IntArrayTest;
 
+import "package:expect/expect.dart";
 import 'dart:typeddata';
 
 void testInt16() {
   Int16List intArray = new Int16List(4);
   intArray[0] = 0;
   intArray[1] = -1;
   intArray[2] = -2;
   intArray[3] = -3;
   for (int i = 0; i < intArray.length; i++) {
     intArray[i]++;
@@ skipping 110 matching lines @@
   testUint64ToSmi();
   for (int i = 0; i < 2000; i++) {
     testInt16();
     testUint16();
     testInt32ToSmi();
     testUint32ToSmi();
     testInt64ToSmi();
     testUint64ToSmi();
   }
 }