io_u: Support fsync for --rw=trimwrite

Even if ddir is determined in get_rw_ddir(), ddir might be updated in
set_rw_ddir().  if td represents trimwrite, it will be updated to either
DDIR_TRIM or DDIR_WRITE even ddir already represents for DDIR_SYNC.

To support DDIR_SYNC(fsync) for trimwrite, this patch checks ddir_sync()
in case of trimwrite not to update the pre-determined ddir.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>

io_u.c

@@ -815,7 +815,7 @@ static void set_rw_ddir(struct thread_data *td, struct io_u *io_u)
 	if (td->o.zone_mode == ZONE_MODE_ZBD)
 		ddir = zbd_adjust_ddir(td, io_u, ddir);
 
-	if (td_trimwrite(td)) {
+	if (td_trimwrite(td) && !ddir_sync(ddir)) {
 		struct fio_file *f = io_u->file;
 		if (f->last_start[DDIR_WRITE] == f->last_start[DDIR_TRIM])
 			ddir = DDIR_TRIM;