tests: fix for 32 bit platforms
tests: fix for 32 bit platforms

On 32 bits the tests would fail with an out of bounds error (in the
tests).

skyportsystems/dns,jdef/dns,benbearchen/dns,ErikDubbelboer/dns,michaelharo/dns,modulexcite/dns,tsenart/dns,cloudflare/dns,Psiphon-Inc/dns,letsencrypt/dns,josephyzhou/dns,asergeyev/dns,rolandshoemaker/dns,curtiszimmerman/dns,bboreham/dns,miekg/dns,ym/go-dns,janstk/dns,Git-Host/dns,ezoic/dns,tempbottle/dns,flebarbe/dns,bragr/dns,AlexCheong/dns,hugozhu/dns,skynet/dns,jmhodges/dns,FiloSottile/dns