The scheme/host/port can either be captured from the HttpHost, or from the absolute URI.
I thought that we should capture the values from HttpHost since those are what's used.
But then I found that all versions except for early 4.x versions use the scheme/host/port from the absolute URI when they get back a host-relative redirect from the server.
So then I got confused, and just made the tests use the same scheme/host/port in both HttpHost and the absolute URI in order to make the redirect tests pass. But we should revisit and tighten up the tests once we decide what should be captured where.