tests: rsend_012_pos: backup/restore in one invocation

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/functional/rsend/rsend_012_pos.ksh

@@ -47,28 +47,21 @@ function edited_prop
 	typeset behaviour=$1
 	typeset ds=$2
 	typeset backfile=$TESTDIR/edited_prop_$ds
+	typeset te=0
 
 	case $behaviour in
 		"get")
+			is_te_enabled && te=1
 			typeset props=$(zfs inherit 2>&1 | \
-				awk '$2=="YES" && $1 !~ /^vol|\.\.\.$/ {print $1}')
-			for item in $props ; do
-				if [[ $item == "mlslabel" ]] && \
-					! is_te_enabled ; then
-					continue
-				fi
-				log_must eval "zfs get -H -o property,value $item $ds >> $backfile"
-			done
+				awk -v te=$te '$2=="YES" && $1 !~ /^vol|\.\.\.$/ && (te || $1 != "mlslabel") {printf("%s,", $1)}')
+			log_must eval "zfs get -Ho property,value ${props%,} $ds >> $backfile"
 			;;
 		"set")
 			if [[ ! -f $backfile ]] ; then
 				log_fail "$ds need backup properties firstly."
 			fi
 
-			typeset prop value
-			while read -r prop value; do
-				log_must zfs set "$prop=$value" "$ds"
-			done < $backfile
+			log_must zfs set $(tr '\t' '=' < $backfile) "$ds"
 			;;
 		*)
 			log_fail "Unrecognized behaviour: $behaviour"