gh-116810: fix memory leak in ssl module (GH-123249)

Resolve a memory leak introduced in CPython 3.10's :mod:`ssl` when the :attr:`ssl.SSLSocket.session` property was accessed. Speeds up read and write access to said property by no longer unnecessarily cloning session objects via serialization.

Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Co-authored-by: Antoine Pitrou <antoine@python.org>