It may happen that two different postcodes normalize to exactly
the same token. In that case we still need two different entries
in the word table. Token lookup will then make sure that the correct
one is choosen.
Fixes#1953.
Always add contents of addr:* tags into address part of the search
table, even when there is no corresponding other name. This keeps
search tolerant to the kind of tagging where parts show up in the
address that have no corresponding object in the database or where
it is only an unaddressable object.
