Update CommandUtils.scala

enable the user can do remote-debugging on the ExcutorRunner Process. we need one flag to enable this function: spark.excutor.debug, an other flag spark.excutor.debug.port to set the port. at normal time, the function is off
if we want do remote-debuggging，weshould use -Dspark.excutor.debug=1 as jvm arguments when we start worker process