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, use the +noauth dig option for all queries in that test, so that the contents of the AUTHORITY section do not influence its outcome.