tests/carp: make a 0.2 second pause before configuring second jail

for all scenarios where both jails have same priority/advskew.  There is a
tiny chance that on both sides carp_master_down() will be executed in
parallel and advertisements will also fly through the bridge(4) in
parallel, thus both sides will switch to MASTER before receiving the
announcement from peer.  This makes the test to fail.  So far this
flakyness was observed for carp:vrrp_v4 only, but in theory it is possible
for any of the patched scenarios.

Note that this sleep does not prolong execution of the tests, as the first
jail is already configured, and if we slept before configuring the second,
we would sleep less in wait_for_carp().

tests/sys/netinet/carp.sh

@@ -90,6 +90,7 @@ basic_v4_body()
 	jexec carp_basic_v4_two ifconfig ${epair_one}b 192.0.2.202/29 up
 	jexec carp_basic_v4_two ifconfig ${epair_one}b add vhid 1 192.0.2.1/29
 
+	sleep 0.2
 	jexec carp_basic_v4_three ifconfig ${epair_two}b 192.0.2.203/29 up
 	jexec carp_basic_v4_three ifconfig ${epair_two}b add vhid 1 \
 	    192.0.2.1/29
@@ -137,6 +138,7 @@ vrrp_v4_body()
 	jexec ${j}_two ifconfig ${epair_one}b 192.0.2.202/29 up
 	jexec ${j}_two ifconfig ${epair_one}b add vhid 1 carpver 3 192.0.2.1/29
 
+	sleep 0.2
 	jexec ${j}_three ifconfig ${epair_two}b 192.0.2.203/29 up
 	jexec ${j}_three ifconfig ${epair_two}b add vhid 1 carpver 3 \
 	    192.0.2.1/29
@@ -182,6 +184,7 @@ unicast_v4_body()
 	jexec carp_uni_v4_two ifconfig ${epair_one}b add vhid 1 \
 	    peer 198.51.100.224 192.0.2.1/32
 
+	sleep 0.2
 	jexec carp_uni_v4_three sysctl net.inet.ip.forwarding=1
 	jexec carp_uni_v4_three ifconfig ${epair_two}b 198.51.100.224/25 up
 	jexec carp_uni_v4_three route add 198.51.100.2 198.51.100.129
@@ -253,6 +256,7 @@ basic_v6_body()
 	jexec carp_basic_v6_two ifconfig ${epair_one}b inet6 add vhid 1 \
 	    2001:db8::0:1/64
 
+	sleep 0.2
 	jexec carp_basic_v6_three ifconfig ${epair_two}b inet6 2001:db8::1:3/64 up no_dad
 	jexec carp_basic_v6_three ifconfig ${epair_two}b inet6 add vhid 1 \
 	    2001:db8::0:1/64
@@ -303,6 +307,7 @@ vrrp_v6_body()
 	jexec ${j}_two ifconfig ${epair_one}b inet6 add vhid 1 carpver 3 \
 	    2001:db8::0:1/64
 
+	sleep 0.2
 	jexec ${j}_three ifconfig ${epair_two}b inet6 2001:db8::1:3/64 up no_dad
 	jexec ${j}_three ifconfig ${epair_two}b inet6 add vhid 1 carpver 3 \
 	    2001:db8::0:1/64
@@ -358,6 +363,7 @@ unicast_v6_body()
 	    peer6 2001:db8:2::2 \
 	    2001:db8::0:1/64
 
+	sleep 0.2
 	jexec carp_uni_v6_three ifconfig ${epair_two}b inet6 2001:db8:2::2/64 \
 	    no_dad up
 	jexec carp_uni_v6_three route -6 add default 2001:db8:2::1
@@ -423,6 +429,7 @@ unicast_ll_v6_body()
 	jexec ${j}_two ifconfig ${epair_one}b inet6 add vhid 1 \
 	    peer6 ${ll_two} \
 	    2001:db8::0:1/64
+	sleep 0.2
 	jexec ${j}_three ifconfig ${epair_two}b inet6 add vhid 1 \
 	    peer6 ${ll_one} \
 	    2001:db8::0:1/64