Stabilize the "gost" system test

Stabilize the "gost" system test

In the "gost" system test, the ./NS RRset returned in the response to
ns2's priming query might not yet be validated when ns2 assembles the
response to the ./SOA query.  If that happens, the ./NS RRset will not
be placed in the AUTHORITY section of the response to the ./SOA query,
triggering a false positive for the "gost" system test as the ./NS RRset
is always present in the response sent by ns1 (since it is authoritative
for the root zone).  As the purpose of the "gost" system test is to
check whether a zone signed using GOST is properly validated and only
positive responses are inspected, use the +noauth dig option for all
queries in that test, so that the contents of the AUTHORITY section do
not influence its outcome.