Fix bug in web socket close handling

tests/standalone/io/web_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");
 
 void testRequestResponseClientCloses(
     int totalConnections, int closeStatus, String closeReason) {
   HttpServer server = new HttpServer();
@@ skipping 132 matching lines @@
     Expect.equals(HttpStatus.BAD_REQUEST, response.statusCode);
     client.shutdown();
     server.close();
   };
 }
 
 main() {
   testRequestResponseClientCloses(2, null, null);
   testRequestResponseClientCloses(2, 3001, null);
   testRequestResponseClientCloses(2, 3002, "Got tired");
-  testRequestResponseServerCloses(1, null, null);
+  testRequestResponseServerCloses(2, null, null);
   testRequestResponseServerCloses(2, 3001, null);
   testRequestResponseServerCloses(2, 3002, "Got tired");
   testNoUpgrade();
   testUsePOST();
 }