The pft_ping.py and sniffer.py tool is moved from tests/sys/netpfil/pf to tests/sys/netpfil/common directory because these tools are to be used in common for all the firewalls. Submitted by: Ahsan Barkati Reviewed by: kp, thj Sponsored by: Google, Inc. (GSoC 2019) Differential Revision: https://reviews.freebsd.org/D21276