t5551: do not confirm that bogus url cannot be used

t5551: do not confirm that bogus url cannot be used

t5551 tries to access a URL with a bogus hostname and confirms that
http.curloptResolve lets us use this otherwise unresolvable name.

Before doing so, though, we confirm that trying to access the bogus
hostname without http.curloptResolve fails as expected. This isn't
testing Git at all, but is confirming the test's assumptions. That's
often a good thing to do, but in this case it means that we'll actually
try to resolve the external name. Even though it's unlikely that
"gitbogusexamplehost.invalid" would ever resolve, the DNS lookup itself
may take time.

It's probably reasonable to just assume that this obviously-bogus name
would not actually resolve in practice, which lets us reduce our test
suite's dependency on the outside world.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>