xfstest: add fallocate/punch_hole vs AIO/DIO stress test

xfstest: add fallocate/punch_hole vs AIO/DIO stress test

Run random AIO/DIO activity (fio's job:direct_aio_raicer)
random fallocate activity(fio's job:falloc_raicer)
and random punch_hole activity(punch_hole_raicer) on a common
file in parallel. If a race exists, old dio request may rewrite
punched block after it was allocated to another file, we will
catch that by verifier fio's job: "aio-dio-verifier".

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>