Invalid hostname tests can fail if the ISP hijacks NXDOMAIN

Some residential internet service providers use the opportunity of DNS record not found cases and instead of returning NXDOMAIN responses per the standard they return A records that redirect the user to their own portal or search page. This breaks tests like TestConnectionImplementation.testGetClientBadHostname and TestRegionServerHostname.testInvalidRegionServerHostnameAbortsServer. We should detect this behavior and skip these cases.