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/nat-rw-mark/pretest.dat

@@ -13,6 +13,8 @@ sun::iptables -t mangle -A PREROUTING -d PH_IP_DAVE10 -j MARK --set-mark 20
 sun::ipsec start
 alice::ipsec start
 venus::ipsec start
+sun::expect-connection alice
+sun::expect-connection venus
 alice::expect-connection nat-t
 alice::ipsec up nat-t
 venus::expect-connection nat-t