Remove Expect from core library.

tests/standalone/io/http_redirect_test.dart

 // Copyright (c) 2013, 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:async";
 import "dart:io";
 import "dart:uri";
 
 Future<HttpServer> setupServer() {
   Completer completer = new Completer();
   HttpServer.bind().then((server) {
 
     var handlers = new Map<String, Function>();
     addRequestHandler(String path, void handler(HttpRequest request,
@@ skipping 357 matching lines @@
   testManualRedirect();
   testManualRedirectWithHeaders();
   testAutoRedirect();
   testAutoRedirectWithHeaders();
   testAutoRedirect301POST();
   testAutoRedirect303POST();
   testAutoRedirectLimit();
   testRedirectLoop();
   testRedirectClosingConnection();
 }