arptables: add test cases

Unicast being shown as '00:00:00:00:00:00/01:00:00:00:00:00' looks like
broken output, however, arptables classic did not pretty-print either.

Also add test cases for all targets supported by the original
arptables tool:

-j CLASSIFY
-j MARK
-j mangle

[ yes, mangle target is lower-case 8-( ]

Signed-off-by: Florian Westphal <fw@strlen.de>
4 files changed