testing: Enable firewall for ikev2/compress scenario

Additionally, send a regular (small) ping as the kernel does not
compress small packets and handles those differently inbound.

testing/tests/ikev2/compress/pretest.dat

@@ -1,3 +1,5 @@
+carol::iptables-restore < /etc/iptables.rules
+moon::iptables-restore < /etc/iptables.rules
 carol::ipsec start
 moon::ipsec start
 carol::sleep 2