Make sure we always unsubscribe from a stream, in http-impl.

tests/standalone/io/http_server_early_client_close_test.dart

Index: tests/standalone/io/http_server_early_client_close_test.dart
diff --git a/tests/standalone/io/http_server_early_client_close_test.dart b/tests/standalone/io/http_server_early_client_close_test.dart
index d35aaf4366f1387f9b4a48c247a6afe4b212f131..57a922b0209c027c364a8e269b9747be3d83fca4 100644
--- a/tests/standalone/io/http_server_early_client_close_test.dart
+++ b/tests/standalone/io/http_server_early_client_close_test.dart
@@ -1,6 +1,11 @@
 // 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";