Not robust enough when receveing unexpected RR types

% check-soa -i 1515k.cc        
Internal myerror when processing 1515k.cc.	186	IN	A	108.160.165.11, unexpected record type

This is because one of the two authoritative name servers, ns2 (or instead the GFW in front of it), returns a A RR:

% dig @ns2.dns.com NS 1515k.cc

; <<>> DiG 9.18.1-1ubuntu1.1-Ubuntu <<>> @ns2.dns.com NS 1515k.cc
; (3 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21370
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;1515k.cc.		IN NS

;; ANSWER SECTION:
1515k.cc.		165 IN A 173.231.12.107

;; Query time: 304 msec
;; SERVER: 240e:ff:9000:1100::19f#53(ns2.dns.com) (UDP)
;; WHEN: Fri Sep 16 12:37:58 CEST 2022
;; MSG SIZE  rcvd: 42