Run the cpp/py client sequentially
Run the cpp/py client sequentially

Originally, we launched the cpp and python client simultaneously, but it
seems that the request is never sent on Windows CI(appveyor)
which leads a timeout of  60000ms. So we will launch the two clients
(cpp and python) one by one.

minggangw/rclnodejs-1,RobotWebTools/rclnodejs,minggangw/rclnodejs-1,minggangw/rclnodejs-1,RobotWebTools/rclnodejs,RobotWebTools/rclnodejs,RobotWebTools/rclnodejs,RobotWebTools/rclnodejs,minggangw/rclnodejs-1