testing: Add ikev2/net2net-iptfs scenario

testing/tests/ikev2/net2net-iptfs/pretest.dat

@@ -0,0 +1,7 @@
+moon::iptables-restore < /etc/iptables.rules
+sun::iptables-restore < /etc/iptables.rules
+moon::systemctl start strongswan
+sun::systemctl start strongswan
+moon::expect-connection gw-gw
+sun::expect-connection gw-gw
+moon::swanctl --initiate --child net-net 2> /dev/null