Test servers don't always start up in time

[jonathanstowe]

It seems that the tests that use some test server intermittently fail because the test server hasn't completely started by the time it is needed.

This is specifically the /230-binary-request.t and t/250-issue-144.t

I guess that utterly slack thing to do would be to put a sleep in but there may be a better idea. The latter test is somewhat complicated by what the server does which means it can't be checked prior to being used.