#1133: Fixed subpackage without package validation

The validation that checks whether a subpackage without package
should not exist errored whenever a subpackage was present. This was
due to the package member of a Descriptor not correctly being populated.

This specific issue has not been resolved but the validation is changed
to use the actual tag information instead of the enriched package
information. This provides a more accurate reflection of the situation
and fixes the issue at the same time.