tests: vfs_path_string_convert - set terminal encoding to UTF-8 to avoid invalid conversions

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

tests/lib/vfs/vfs_path_string_convert.c

@@ -48,7 +48,7 @@ static struct vfs_class vfs_test_ops1, vfs_test_ops2, vfs_test_ops3;
 static void
 setup (void)
 {
-    str_init_strings (NULL);
+    str_init_strings ("UTF-8");
 
     vfs_init ();
     vfs_init_localfs ();