testing: Add an acert test that forces a fallback connection based on groups

testing/tests/ikev2/acert-fallback/pretest.dat

@@ -0,0 +1,6 @@
+moon::iptables-restore < /etc/iptables.rules
+carol::iptables-restore < /etc/iptables.rules
+moon::ipsec start
+carol::ipsec start
+carol::sleep 1
+carol::ipsec up home