use LC_ALL, not LANG, for forcing C

testsuite/ls/ls-l-works

@@ -1,4 +1,4 @@
 [ -n "$d" ] || d=..
-LANG=C ls -l "$d" > logfile.gnu
+LC_ALL=C ls -l "$d" > logfile.gnu
 busybox ls -l "$d" > logfile.bb
 diff -w logfile.gnu logfile.bb

testsuite/ls/ls-s-works

@@ -1,4 +1,4 @@
 [ -n "$d" ] || d=..
-LANG=C ls -1s "$d" > logfile.gnu
+LC_ALL=C ls -1s "$d" > logfile.gnu
 busybox ls -1s "$d" > logfile.bb
 cmp logfile.gnu logfile.bb