Kernel: Fix unix domain socket close detection

Also rework resolver's send format and convert test-tcp and nslookup to
use getaddrinfo

userspace/programs/resolver/main.cpp

@@ -316,6 +316,7 @@ BAN::Optional<BAN::IPv4Address> resolve_from_dns_cache(BAN::HashMap<BAN::String,
 	{
 		if (time(nullptr) > it->value.valid_until)
 		{
+			dprintln("{} timedout", it->key);
 			dns_cache.remove(it);
 			return {};
 		}