the resolver test checks that the correct number of fetches have
been sent NS rrsets of a given size, but it formerly did so by
counting queries received by the authoritative server, which could
result in an off-by-one count if one of the queries had been resent
due to a timeout or a port number collision.
this commit changes the test to count fetches initiated by the
resolver, which should prevent the intermittent test failure, and
is the actual datum we were interested in anyway.
069625cccb