Add an sslapitest for early callback

Add an sslapitest for early callback

Make sure that we can stop handshake processing and resume it later.
Also check that the cipher list and compression methods are sane.
Unfortunately, we don't have the client-side APIs needed to force
a specific (known) session ID to be sent in the ClientHello, so
that accessor cannot be tested here.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2279)