Enable standalone/io/http_test, splitting it into three separate tests.

tests/standalone/io/http_server_socket_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:io");
 #import("dart:isolate");
 
 class ExpectedDataOutputStream implements OutputStream {
   ExpectedDataOutputStream(List<int> this._data,
                            int this._cutoff,
@@ skipping 151 matching lines @@
   Function _onConnection;
   Function _onError;
   Set<Socket> _sockets;
 }
 
 void testSocketClose() {
   ServerSocketMock serverSocket = new ServerSocketMock("0.0.0.0", 5432, 5);
 
   HttpServer server = new HttpServer();
   server.listenOn(serverSocket);
-  void testContent(String request,
-                   String response,
+  void testContent(String requestString,
+                   String responseString,
                    [int okayFrom = 0,
                     bool expectError = true]) {
     // Inner callback to actually run a given setting.
     void runSettings(int cutoff,
                      bool closeAsError,
                      bool expectError) {
       server.defaultRequestHandler =
           (HttpRequest request, HttpResponse response) {
             request.inputStream.onData = () {
             };
             request.inputStream.onClosed = () {
               response.outputStream.close();
             };
           };
 
       if (expectError) {
         ReceivePort port = new ReceivePort();
         server.onError = (Exception error) {
           port.close();
         };
       } else {
         server.onError = (Exception error) {
           Expect.fail("An error was not expected: $error");
         };
       }
 
-      serverSocket.spawnSocket(request, response, cutoff, closeAsError);
+      serverSocket.spawnSocket(requestString, responseString,
+                               cutoff, closeAsError);
       // TODO(ajohnsen): Validate HttpServers number of connections.
     }
-    for (int i = 1; i < response.length; i++) {
-      bool _expectError = expectError && i < response.length - okayFrom;
+    for (int i = 1; i < responseString.length; i++) {
+      bool _expectError = expectError && i < responseString.length - okayFrom;
       runSettings(i, false, _expectError);
       runSettings(i, true, _expectError);
     }
   }
   testContent(
       "GET / HTTP/1.1\r\nKeep-Alive: False\r\n\r\n",
       "HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\nconnection: close"
       "\r\n\r\n0\r\n\r\n");
 
   server.close();
 }
 
 void main() {
   testSocketClose();
 }