Refactor QNAME minimization to use NS records and check for cached NODATA
requested to merge 3325-strict-qname-minimisation-should-check-for-cached-nodata-for-ns-name into main
Use NS rather than A records for qname-minimization relaxed
Remove all references to DNS_FETCHOPT_QMIN_USE_A and adjust the expected tests results in the qmin system test.
Edited by Ondřej Surý