ZTS: explicitly strip whitespace for broken wc(1) implementations

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13032

tests/zfs-tests/tests/functional/alloc_class/alloc_class_012_pos.ksh

@@ -34,6 +34,7 @@ function file_in_special_vdev # <dataset> <inode>
 	typeset dataset="$1"
 	typeset inum="$2"
 	typeset num_normal=$(echo $ZPOOL_DISKS | wc -w)
+	num_normal=${num_normal##* }
 
 	zdb -dddddd $dataset $inum | awk -v d=$num_normal '{
 # find DVAs from string "offset level dva" only for L0 (data) blocks

tests/zfs-tests/tests/functional/cli_root/zpool_events/zpool_events_clear.ksh

@@ -44,6 +44,7 @@ done
 # wait a bit to allow the kernel module to process new events
 zpool_events_settle
 EVENTS_NUM=$(zpool events -H | wc -l)
+EVENTS_NUM=${EVENTS_NUM##* }
 
 # 3. Verify 'zpool events -c' successfully clear new events
 CLEAR_OUTPUT=$(zpool events -c)

tests/zfs-tests/tests/functional/mv_files/mv_files_common.kshlib

@@ -115,7 +115,7 @@ function mv_files
 function count_files
 {
         typeset -i file_num
-        file_num=$(find $1 -type f -print | wc -l)
+        file_num=$(find $1 -type f -print | wc -l | tr -d ' ')
         (( file_num != $2 )) && \
                 log_fail "The file number of target directory"\
                         "$2 is not equal to that of the source "\