Add an integration test for WebSocket

Summary:
**Motivation**

See if we can safely run a WebSocket test in Travis CI
Closes https://github.com/facebook/react-native/pull/11433

Differential Revision: D4342024

Pulled By: ericvicenti

fbshipit-source-id: 137fb0c39ed7ea3726e2778d5c0bdac4cef6ab89

IntegrationTests/launchWebSocketServer.command

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+# Copyright (c) 2015-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+# Set terminal title
+echo -en "\033]0;Web Socket Test Server\a"
+clear
+
+THIS_DIR=$(dirname "$0")
+pushd "$THIS_DIR"
+./websocket_integration_test_server.js
+popd
+
+echo "Process terminated. Press <enter> to close the window"
+read