intel/tools/aubinator_error_decode: read HW Context before other batches

intel/tools/aubinator_error_decode: read HW Context before other batches

The hardware context buffer has state that was set before the
batch started. By decoding it first, references to things like
Dynamic State Base Address are decodable in the command batches.

Reviewed-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4246>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4246>