[3.8] gh-108342: Make ssl TestPreHandshakeClose more reliable (GH-108370)

[ambv]

• In preauth tests of test_ssl, explicitly break reference cycles invoving SingleConnectionTestServerThread to make sure that the thread is deleted. Otherwise, the test marks the environment as altered because the threading module sees a "dangling thread" (SingleConnectionTestServerThread). This test leak was introduced by the test added for the fix of issue CVE-2023-40217: Bypass TLS handshake on closed sockets #108310.
• Use support.SHORT_TIMEOUT instead of hardcoded 1.0 or 2.0 seconds timeout.
• SingleConnectionTestServerThread.run() catchs TimeoutError
• Fix a race condition (missing synchronization) in test_preauth_data_to_tls_client(): the server now waits until the client connect() completed in call_after_accept().
• test_https_client_non_tls_response_ignored() calls server.join() explicitly.
• Replace "localhost" with server.listener.getsockname()[0]. (cherry picked from commit 592bacb)

• Issue: test_ssl fails with "env changed" on ARM64 Windows buildbot: thread doesn't catch TimeoutError #108342