Remove deprecated second argument to SendPort.send().

tests/standalone/io/http_read_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";
@@ skipping 120 matching lines @@
   SendPort get dispatchSendPort => _dispatchPort.sendPort;
 
   void dispatch(message) {
     IsolatedHttpServerCommand command = message[0];
     SendPort replyTo = message[1];
     if (command.isStart) {
       try {
         HttpServer.bind("127.0.0.1", 0).then((server) {
           _server = server;
           _server.listen(_requestReceivedHandler);
-          replyTo.send(
-              new IsolatedHttpServerStatus.started(_server.port), null);
+          replyTo.send(new IsolatedHttpServerStatus.started(_server.port));
         });
       } catch (e) {
-        replyTo.send(new IsolatedHttpServerStatus.error(), null);
+        replyTo.send(new IsolatedHttpServerStatus.error());
       }
     } else if (command.isStop) {
       _server.close();
       _dispatchPort.close();
-      replyTo.send(new IsolatedHttpServerStatus.stopped(), null);
+      replyTo.send(new IsolatedHttpServerStatus.stopped());
     } else if (command.isChunkedEncoding) {
       _chunkedEncoding = true;
     }
   }
 
   void _requestReceivedHandler(HttpRequest request) {
     var requestHandler =_requestHandlers[request.uri.path];
     if (requestHandler != null) {
       requestHandler(request);
     } else {
@@ skipping 49 matching lines @@
   }
 
   server.setServerStartedHandler(runTest);
   server.start(chunkedEncoding);
 }
 
 void main() {
   testRead(true);
   testRead(false);
 }