tests: check ethernet type in arp test case
tests: check ethernet type in arp test case

Add assertions to verify correct ethernet type field in ARP test case.

Type: test

Signed-off-by: Elias Rudberg <6e47e6550991154ffa3988d148e1634d2421b18a@bahnhof.net>
Change-Id: I1d2671b0ab2b4dcb53dab4b54bf93578d6bc86a3

FDio/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp