Currently, there are some unit tests that are failing on Windows due to
various reasons:
- getHostDNSConfig is reading a resolv.conf file. However, we don't have
that on Windows. Instead, we can get the DNS server list and the DNS
suffix list from Windows itself.
On Windows, getHostDNSConfig will now return the host's DNS configuration
if the given resolverConfig is "Host". If it's not "Host" or an empty string,
an error will be returned.
Based on the code from kubernetes/test/images/agnhost/dns/dns_windows.go
