automated/linux/piglit: Add support to use final result file

If the piglit run is complete it creates a single file with all
the results (results.json.bz2) and delete previous temp result files,
test if the final result file exists and use it.

Change-Id: Ia33d88ce536c2688d4d784fc081cd48693e16dcb
Signed-off-by: Aníbal Limón <anibal.limon@linaro.org>
2 files changed