apparmor-session-lockdown: produce more useful diagnostics

The list of profiles and processes isn't all that long. If we're
going to make assertions about this information, we should
probably show it first.

Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D3448