selftests net: add UDP GRO fraglist + bpf self-tests

When NET_F_F_GRO_FRAGLIST is enabled and bpf_skb_change_proto is used,
check if udp packets and tcp packets are successfully delivered to user
space. If wrong udp packets are delivered, udpgso_bench_rx will exit
with "Initial byte out of range"

Signed-off-by: Maciej enczykowski <maze@google.com>
Signed-off-by: Lina Wang <lina.wang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>