Implement a new feature for ping(8) - sweeping pings. In a sweeping
ping ICMP payload of packets being sent is increased with given step.
Sweeping pings are useful for testing problematic channels, MTU
issues or traffic policing functions in networks.
PR: bin/82625
Submitted by: Chris Hellberg <chellberg juniper.net> (with some cleanups)
Approved by: re (kensmith)
10a0fa240e