:l_flag:: be more aggressive when normalizing whitespace

Save output from ls -ldT and stat -l, then normalize all repeating whitespace using
sed to single column spaces.

This makes the test flexible with single-digit days, etc, similar to r320723. This
approach is just a bit more of a hammer approach because of how the columns are
ordered/spaced in both ls and stat.

MFC after:	1 week
MFC with:	r319841

usr.bin/stat/tests/stat_test.sh

@@ -60,14 +60,23 @@ l_flag_body()
 
 	paths="a b c d"
 
+	ls_out=ls.output
+	stat_out=stat.output
+
 	# NOTE:
 	# - Even though stat -l claims to be equivalent to `ls -lT`, the
 	#   whitespace is a bit more liberal in the `ls -lT` output.
 	# - `ls -ldT` is used to not recursively list the contents of
 	#   directories.
 	for path in $paths; do
-		atf_check -o inline:"$(ls -ldT $path | sed -e 's,  , ,g')\n" \
-		    stat -l $path
+		atf_check -o save:$ls_out ls -ldT $path
+		cat $ls_out
+		atf_check -o save:$stat_out stat -l $path
+		cat $stat_out
+		echo "Comparing normalized whitespace"
+		atf_check sed -i '' -E -e 's/[[:space:]]+/ /g' $ls_out
+		atf_check sed -i '' -E -e 's/[[:space:]]+/ /g' $stat_out
+		atf_check cmp $ls_out $stat_out
 	done
 }