Repair EAP-FAST session resumption

EAP-FAST session resumption relies on handshake message lookahead
to determine server intentions. Commits
980bc1ec
and
7b3ba508


removed the lookahead so broke session resumption.

This change partially reverts the commits and brings the lookahead back
in reduced capacity for TLS + EAP-FAST only. Since EAP-FAST does not
support regular session tickets, the lookahead now only checks for a
Finished message.

Regular handshakes are unaffected by this change.

Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Matt Caswell <matt@openssl.org>