[9.18] Use NS rather than A records for qname-minimization relaxed
requested to merge 3325-strict-qname-minimisation-should-check-for-cached-nodata-for-ns-name-9.18 into bind-9.18
Remove all references to DNS_FETCHOPT_QMIN_USE_A and adjust the expected tests results in the qmin system test.
(cherry picked from commit dd00b3c5)
Closes #3325 (closed), #3326 (closed), #3331 (closed)
Backport of !6267 (merged)