testing: Avoid delays with ping by using -W and -i options

With -W we reduce timeouts when we don't expect a response.  With -i the
interval between pings is reduced (mostly in case of auto=route where
the first ping yields no reply).

testing/tests/pfkey/protoport-route/pretest.dat

@@ -5,4 +5,4 @@ carol::ipsec start
 carol::expect-connection home-icmp
 carol::expect-connection home-ssh
 carol::ssh PH_IP_ALICE hostname
-carol::ping -c 1 PH_IP_ALICE > /dev/null
+carol::ping -c 1 -W 1 PH_IP_ALICE > /dev/null