Revert "Add new InternetAddress class with a static lookup function (including IPv6 results)"

tests/standalone/io/http_server_early_client_close_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:isolate";
 
 void sendData(List<int> data, int port) {
@@ skipping 128 matching lines @@
     server.listen((request) {
       var subscription;
       subscription = request.listen(
           (_) {},
           onError: (error) {
             // subscription.cancel should not trigger an error.
             subscription.cancel();
             server.close();
           });
     });
-    Socket.connect("127.0.0.1", server.port)
+    Socket.connect("localhost", server.port)
         .then((socket) {
           socket.write("GET / HTTP/1.1\r\n");
           socket.write("Content-Length: 10\r\n");
           socket.write("\r\n");
           socket.write("data");
           socket.close();
           socket.listen((_) {}, onError: (_) {});
           socket.done.catchError((_) {});
         });
   });
 }
 
 void main() {
   testEarlyClose1();
   testEarlyClose2();
   testEarlyClose3();
 }