ZTS: block_cloning: Use numeric sort for get_same_blocks

Reviewed-by: Kay Pedersen <mail@mkwg.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by:  Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes #15614

tests/zfs-tests/tests/functional/block_cloning/block_cloning.kshlib

@@ -53,6 +53,6 @@ function get_same_blocks
 	    awk '/ L0 / { print l++ " " $3 " " $7 }' > $zdbout.a
 	zdb $KEY -vvvvv $3 -O $4 | \
 	    awk '/ L0 / { print l++ " " $3 " " $7 }' > $zdbout.b
-	echo $(sort $zdbout.a $zdbout.b | uniq -d | cut -f1 -d' ')
+	echo $(sort -n $zdbout.a $zdbout.b | uniq -d | cut -f1 -d' ')
 }