Log ZTS test name to dmesg

Log each test name to dmesg to help post-mortem test failures.
Specifically, to help debug #10940.

Signed-off-by: Tony Hutter <hutter2@llnl.gov>

tests/zfs-tests/include/libtest.shlib

@@ -279,6 +279,10 @@ function default_setup_noexit
 	typeset no_mountpoint=$4
 	log_note begin default_setup_noexit
 
+	# Crudely log to dmesg which test we're running for post-mortem
+	me=`ps a | grep -Eo '[^ ]+ksh$' | head -n 1`
+	echo "ZTS: running $me" > /dev/kmsg
+
 	if is_global_zone; then
 		if poolexists $TESTPOOL ; then
 			destroy_pool $TESTPOOL