selftests: add a test case for mirred egress to ingress

selftests: add a test case for mirred egress to ingress

add a selftest that verifies the correct behavior of TC act_mirred egress
to ingress: in particular, it checks if the dst_entry is removed from skb
before redirect egress -> ingress. The correct behavior is: an ICMP 'echo
request' generated by ping will be received and generate a reply the same
way as the one generated by mausezahn.

Suggested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>