[Piglit] Add incomplete file for tests as they start

[Mark Janes]

Series is

Reviewed-by: Mark Janes <mark.a.janes at intel.com>

Dylan Baker <baker.dylan.c at gmail.com> writes:

> One of the more interesting problems for piglit, especially with
> hardware bring-up where bad code may result in the system crashing, is
> to know what test actually crashed the system.
>
> This series is meant to address that problem. It does so by adding a new
> status, the incomplete status, which is used by the backend to write out
> a file for a test before the test starts running. When the test
> completes this status is overwritten with the final result. If the test
> is never overwritten (say the system crashes) it remains incomplete.