[3.14] gh-142489: Increase ssl_handshake_timeout in asyncio tests (GH-142523) (#142545)

gh-142489: Increase ssl_handshake_timeout in asyncio tests (GH-142523)

Replace SHORT_TIMEOUT with LONG_TIMEOUT for very slow CIs.
And add the HANDSHAKE_TIMEOUT constant.
(cherry picked from commit dc3ece2bc06d56c21ef81f86424b4598880ba1c8)

Co-authored-by: Victor Stinner <vstinner@python.org>