bpo-35031: Fix test_start_tls_server_1 on FreeBSD buildbots (GH-10011)

Some FreeBSD buildbots fail to run this test as the eof was not being received by the server if the size is not big enough. This behaviour only appears if the client is using TLS1.3.

Lib/test/test_asyncio/test_sslproto.py

@@ -2,6 +2,7 @@
 
 import logging
 import socket
+import sys
 import unittest
 from unittest import mock
 try:
@@ -429,6 +430,12 @@ class BaseStartTLS(func_tests.FunctionalTestCaseMixin):
 
         server_context = test_utils.simple_server_sslcontext()
         client_context = test_utils.simple_client_sslcontext()
+        if sys.platform.startswith('freebsd'):
+            # bpo-35031: Some FreeBSD buildbots fail to run this test
+            # as the eof was not being received by the server if the payload
+            # size is not big enough. This behaviour only appears if the
+            # client is using TLS1.3.
+            client_context.options |= ssl.OP_NO_TLSv1_3
 
         def client(sock, addr):
             sock.settimeout(self.TIMEOUT)