Second round of cleanups for new optional parameter semantics.

tests/standalone/io/http_connection_close_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("dart:isolate");
 #import("dart:io");
 
 void testHttp10Close() {
   HttpServer server = new HttpServer();
-  server.listen("127.0.0.1", 0, 5);
+  server.listen("127.0.0.1", 0, backlog: 5);
 
   Socket socket = new Socket("127.0.0.1", server.port);
   socket.onConnect = () {
     List<int> buffer = new List<int>(1024);
     socket.outputStream.writeString("GET / HTTP/1.0\r\n\r\n");
     socket.onData = () => socket.readList(buffer, 0, buffer.length);
     socket.onClosed = () {
       socket.close(true);
       server.close();
     };
   };
 }
 
 void testHttp11Close() {
   HttpServer server = new HttpServer();
-  server.listen("127.0.0.1", 0, 5);
+  server.listen("127.0.0.1", 0, backlog: 5);
 
   Socket socket = new Socket("127.0.0.1", server.port);
   socket.onConnect = () {
     List<int> buffer = new List<int>(1024);
     socket.outputStream.writeString(
         "GET / HTTP/1.1\r\nConnection: close\r\n\r\n");
     socket.onData = () => socket.readList(buffer, 0, buffer.length);
     socket.onClosed = () {
       socket.close(true);
       server.close();
     };
   };
 }
 
 main() {
   testHttp10Close();
   testHttp11Close();
 }