ci/freedreno: Move our skips lists over to being known-flakes lists.

ci/freedreno: Move our skips lists over to being known-flakes lists.

This makes sure that we keep executing the tests so that we can get our
alerts in IRC and know whether the tests are still flaking.  It also keeps
us from having adjustments to the skip list causing failures/flakes to
move to different tests (as seen with a530 having to move some xfails
around after changing the skip list)

Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6392>