verify: disable write sequence checks with norandommap and iodepth > 1

verify: disable write sequence checks with norandommap and iodepth > 1

With norandommap for async I/O engines specifying I/O depth > 1, it is
possible that two or more writes with the same offset are queued at once.
When fio tries to verify the block, it may find a numberio mismatch
because the writes did not land on the media in the order that they were
queued. Avoid these spurious failures by disabling sequence number
checking. Users will still be able to enable sequence number checking
if they explicitly set the verify_header_sequence option.

fio -name=verify -ioengine=libaio -rw=randwrite -verify=sha512 -direct=1 \
-iodepth=32 -filesize=16M -bs=512 -norandommap=1 -debug=io,verify

Below is the truncated log for the above command demonstrating the issue.
This includes extra log entries when write sequence number is saved and
retrieved.

set: io_u->numberio=28489, off=0x5f2400
queue: io_u 0x5b8039e30d40: off=0x5f2400,len=0x200,ddir=1,file=verify.0.0
set: io_u->numberio=28574, off=0x5f2400
iolog: overlap 6235136/512, 6235136/512
queue: io_u 0x5b8039e75500: off=0x5f2400,len=0x200,ddir=1,file=verify.0.0
complete: io_u 0x5b8039e75500: off=0x5f2400,len=0x200,ddir=1,file=verify.0.0
complete: io_u 0x5b8039e30d40: off=0x5f2400,len=0x200,ddir=1,file=verify.0.0

retrieve: io_u->numberio=28574, off=0x5f2400
queue: io_u 0x5b8039e1db40: off=0x5f2400,len=0x200,ddir=0,file=verify.0.0

bad header numberio 28489, wanted 28574 at file verify.0.0 offset 6235136, length 512 (requested block: offset=6235136, length=512)

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>