fix: Fix the nslookup system test

The nslookup system test checks the count of resolved addresses in the CNAME tests using a 'grep' match on the hostname, and ignoring lines containing the 'canonical name' string. In order to protect the check from intermittent failures like the 'address in use' warning message, which then automatically resolves after a retry, edit the 'grep' matching string to also ignore the comments (as the mentioned warning message is a comment which contains the hostname).

Closes #4948