As you likely saw, no, this wasn't intentional. That said, newer versions of the buildfarm code already use https://buildfarm.postgresql.org in the example config and any buildfarm members impacted should be able to update their config to use that.
Perhaps we should post that to the buildfarm members list...?
I think that would be a good idea in general, so if someone has the time to over it and do that, big +1 for that. (I don't think it's easy to machine-change it)
But given that we should still try to ressurect that domain name, there are likely a lot of links that are going to stay around for quite some time.