Remove Expect from core library.

tests/standalone/io/chunked_stream_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.
 
+import "package:expect/expect.dart";
 import "dart:io";
 import "dart:isolate";
 
 void test1() {
   void testWithChunkSize(var data, int chunkSize, Function testDone) {
     ListInputStream list_input_stream = new ListInputStream();
     list_input_stream.write(data);
     list_input_stream.markEndOfStream();
     ChunkedInputStream stream = new ChunkedInputStream(list_input_stream);
     int chunkCount = 0;
@@ skipping 116 matching lines @@
   s.write([4, 5, 6]);  // 7 bytes written to stream.
 
   donePort.receive((x,y) => donePort.close());
 }
 
 
 main() {
   test1();
   test2();
 }