tests: nonspecific cleanup

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13259

tests/zfs-tests/tests/perf/perf.shlib

@@ -265,7 +265,7 @@ function apply_zinject_delays
 	typeset idx=0
 	while [[ $idx -lt "${#ZINJECT_DELAYS[@]}" ]]; do
 		[[ -n ${ZINJECT_DELAYS[$idx]} ]] || \
-		    log_must "No zinject delay found at index: $idx"
+		    log_fail "No zinject delay found at index: $idx"
 
 		for disk in $DISKS; do
 			log_must zinject \