hints: fix names inside home.arpa.
Reported on https://forum.turris.cz/t/knot-resolver-with-local-fqdn-hostnames/19034/8
I write it as three comparisons, as it seems like a simple way of still running only a single comparison in the typical case of QNAME not falling under .arpa.
Tested just quickly, manually. This chunk of code already is replaced for kresd >= 6.0.0.