selftests: extend zerocopy tests to udp

Both msg_zerocopy and udpgso_bench have udp zerocopy variants.
Exercise these as part of the standard kselftest run.

With udp, msg_zerocopy has no control channel. Ensure that the
receiver exits after the sender by accounting for the initial
delay in starting them (in msg_zerocopy.sh).

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/msg_zerocopy.sh

@@ -25,6 +25,8 @@ readonly path_sysctl_mem="net.core.optmem_max"
 if [[ "$#" -eq "0" ]]; then
 	$0 4 tcp -t 1
 	$0 6 tcp -t 1
+	$0 4 udp -t 1
+	$0 6 udp -t 1
 	echo "OK. All tests passed"
 	exit 0
 fi