tests: add subsurface-shot test
This is marked as a FAIL_TEST, because the last image comparison fails
due to a bug in Weston.
Jointly authored by Pekka and Emilio.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Signed-off-by: Emilio Pozuelo Monfort <emilio.pozuelo@collabora.co.uk>
Reviewed-by: Micah Fedke <micah.fedke@collabora.co.uk>
[Pekka: move weston-tests-env as terminator to EXTRA_DIST, change
ok/FAIL to PASS/FAIL, write diff image only on fail.]
Acked-by: Quentin Glidic <sardemff7+git@sardemff7.net>