tests/shell: get rid of static variables

Stop using static variables and clean up when we're done.

[Emilio: update to latest weston_layer API]

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>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
[Pekka: fix build after previous commit's fix]
1 file changed