Fix a test which needed an error handler after r17064

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:async";
 import "dart:io";
 import "dart:uri";
 
 void testHttp10Close(bool closeRequest) {
@@ skipping 25 matching lines @@
     if (closeRequest) socket.outputStream.close();
     socket.onData = () => socket.readList(buffer, 0, buffer.length);
     socket.onClosed = () {
       if (!closeRequest) socket.close(true);
       server.close();
     };
   };
 }
 
 void testStreamResponse() {
+  Timer timer;
   var server = new HttpServer();
+  server.onError = (e) {
+    server.close();
+    timer.cancel();
+  };
   server.listen("127.0.0.1", 0, backlog: 5);
   server.defaultRequestHandler = (var request, var response) {
-    new Timer.repeating(10, (x) {
+    timer = new Timer.repeating(10, (_) {
       Date now = new Date.now();
       try {
         response.outputStream.writeString(
             'data:${now.millisecondsSinceEpoch}\n\n');
       } catch (e) {
-        x.cancel();
+        timer.cancel();
         server.close();
       }
     });
   };
 
   var client = new HttpClient();
   var connection =
       client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}"));
   connection.onResponse = (resp) {
     int bytes = 0;
     resp.inputStream.onData = () {
       bytes += resp.inputStream.read().length;
       if (bytes > 100) {
         client.shutdown(force: true);
       }
     };
   };
   connection.onError = (e) => Expect.isTrue(e is HttpException);
 }
 
 main() {
   testHttp10Close(false);
   testHttp10Close(true);
   testHttp11Close(false);
   testHttp11Close(true);
   testStreamResponse();
 }