This fixes tests that were added after 113f04e664 as the tests would
fail otherwise.
We bring back "Proxy-Connection: Keep-Alive" now unconditionally to fix
regressions with old and stupid proxies, but we could possibly switch to
using it only for CONNECT or only for NTLM in a future if we want to
gradually reduce it.
Fixes#954
Reported-by: János Fekete
Mostly in order to support broken web sites that redirect to broken URLs
that are accepted by browsers.
Browsers are typically even more leniant than this as the WHATWG URL
spec they should allow an _infinite_ amount. I tested 8000 slashes with
Firefox and it just worked.
Added test case 1141, 1142 and 1143 to verify the new parser.
Closes#791