Always connect using HOST_NAME, but swicth on host source on secure upgrade, in secure_upgrade test.

tests/standalone/io/socket_upgrade_to_secure_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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
-const HOST_IP = "127.0.0.1";
 const HOST_NAME = "localhost";
 const CERTIFICATE = "localhost_cert";
 
 // This test creates a server and a client connects. After connecting
 // and an optional initial handshake the connection is secured by
 // upgrading to a secure connection The client then writes and the
 // server echos. When the server has finished its echo it
 // half-closes. When the client gets the close event is closes fully.
 //
 // The test can be run in different configurations based on
@@ skipping 119 matching lines @@
             completer.complete(null);
           }
         },
         onDone: () => Expect.fail("Should not be called")
     );
     socket.add(createHandshakeTestData());
     return completer.future;
   }
 
   Future<SecureSocket> connectClient(int port) {
-    var host = hostnameInConnect ? HOST_NAME : HOST_IP;
     if (!handshakeBeforeSecure) {
-      return Socket.connect(host, port).then((socket) {
+      return Socket.connect(HOST_NAME, port).then((socket) {
         var future;
         if (hostnameInConnect) {
           future = SecureSocket.secure(socket);
         } else {
           future = SecureSocket.secure(socket, host: HOST_NAME);
         }
         return future.then((secureSocket) {
           Expect.throws(() => socket.add([0]));
           return secureSocket;
         });
       });
     } else {
-      return Socket.connect(host, port).then((socket) {
+      return Socket.connect(HOST_NAME, port).then((socket) {
         return runClientHandshake(socket).then((_) {
             var future;
             if (hostnameInConnect) {
               future = SecureSocket.secure(socket);
             } else {
               future = SecureSocket.secure(socket, host: HOST_NAME);
             }
             return future.then((secureSocket) {
               Expect.throws(() => socket.add([0]));
               return secureSocket;
@@ skipping 37 matching lines @@
   SecureSocket.initialize(database: certificateDatabase.toNativePath(),
                           password: 'dartdart',
                           useBuiltinRoots: false);
   test(false, false);
   test(true, false);
   test(false, true);
   test(true, true);
   test(false, true, true);
   test(true, true, true);
 }