Following the previous 2 commits also move ecpointformats out of session

The previous 2 commits moved supported groups and ciphers out of the
session object to avoid race conditions. We now also move ecpointformats
for consistency. There does not seem to be a race condition with access
to this data since it is only ever set in a non-resumption handshake.
However, there is no reason for it to be in the session.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/9176)