Skip this test if the atf working directory has not enough space

for the created image.

tests/sbin/newfs_msdos/t_create.sh

@@ -1,4 +1,4 @@
-# $NetBSD: t_create.sh,v 1.3 2014/01/05 12:59:03 martin Exp $
+# $NetBSD: t_create.sh,v 1.4 2020/03/15 10:15:16 martin Exp $
 #
 # Copyright (c) 2012 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -31,6 +31,11 @@ validfat32_head() {
 }
 validfat32_body() {
 
+	AVAIL=$( df -m ${TMPDIR} | awk '{if (int($4) > 0) print $4}' )
+	if [ $AVAIL -lt 34 ]; then
+		atf_skip "not enough free space in working directory"
+	fi
+
 	atf_check -s eq:0 -o ignore -e ignore \
 	    newfs_msdos -b 512 -C 33m -F 32 msdos.img
 #	fsck_msdos/newfs_msdos have been fixed