drm/i915/selftests: Reorder error cleanup for whitelist checking

Reorder the error paths so that we unwind all the locals from any error
path and so avoid setting off divers alarum in case we find an error in
case we find an error.

References: https://bugs.freedesktop.org/show_bug.cgi?id=111048


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190708152321.22187-1-chris@chris-wilson.co.uk