testing: Add expect-connection calls for all tests and hosts

There are some exceptions (e.g. those that use auto=start or p2pnat).

testing/tests/ikev2/double-nat/pretest.dat

@@ -6,5 +6,6 @@ sun::iptables -t nat -A POSTROUTING -o eth0 -s 10.2.0.0/16 -p tcp -j SNAT --to-s
 sun::iptables -t nat -A PREROUTING -i eth0 -s PH_IP_MOON -p udp -j DNAT --to-destination PH_IP_BOB
 alice::ipsec start
 bob::ipsec start
+bob::expect-connection nat-t
 alice::expect-connection nat-t
 alice::ipsec up nat-t