Instead of manually specifying success or failure.

Based on test_return_status() in ntoskrnl. The changes in this patch don't
affect device IRPs, but the tests show the heuristic that Windows uses, and in
practice it turns out to be correct for all known asyncs.
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>