many tests are wrong, since use multiple HTTP/1.0 answers without keep-alive

[socketpair]

It seems many tests are wrong, since use multiple HTTP/1.0 answers without connection: keep-alive

AFAIK, if request was HTTP/1.1 (as in many tests)

1. HTTP/1.1-aware server should answer with HTTP/1.1 response
2. not HTTP/1.1-aware(i.e. HTTP/1.0 only) server MUST close connection after serving response
3. RFC does not document HTTP/1.0 + Connection: keep-alive, but we should consider that HTTP/1.0 server supports Connection: keep-alive.

So, after that, these tests should be changed to use HTTP/1.1 for responses.

I can create PR after approving that.