ci/x86: speed up piglit testing

Add python3 packages to speed up piglit run.

 - lxml. An accelerated python xml library using libxml2 (http://lxml.de/)
 - simplejson. A fast C based implementation of the python json library.
   (https://simplejson.readthedocs.org/en/latest/)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7379>
2 files changed