Change TLS 1.3 cipher suite settings for compatibility with OpenSSL
1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3 cipers enabled by
default.

Also update multissltests to test with latest OpenSSL.

Signed-off-by: Christian Heimes <christian@python.org>.
(cherry picked from commit 3e630c541b35c96bfe5619165255e559f577ee71)
Co-authored-by: Christian Heimes <christian@python.org>