tests: Add broken files for all broken tests

tests: Add broken files for all broken tests

Each broken file contains the rough frequency of brokeness as well
as a brief explanation of what happens when it breaks. Estimates
of failure rates are not statistically significant and can vary
run to run.

This is really just a view from my window. Tests were done on a
small VM with the default loop devices, not real hardware. We've
seen different kernel configurations can cause bugs to appear as well
(ie. different block schedulers). It may also be that different race
conditions will be seen on machines with different performance
characteristics.

These annotations were done with the kernel currently in md/md-next:

 facef3b96c5b ("md: Notify sysfs sync_completed in md_reap_sync_thread()")

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>