Fix the Windows buildbots.

ZeroIntensity · ZeroIntensity · commit 6da074eb12a8 · 2025-08-09T14:23:59.000-04:00
Apparently, settimeout() implicitly makes the socket non-blocking.
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
@@ -4642,6 +4642,7 @@ def background(sock):
                                             server_hostname=hostname) as sock:
                 sock.connect((HOST, server.port))
                 sock.settimeout(1)
+                sock.setblocking(1)
                 # Ensure that the server is ready to accept requests
                 sock.sendall(b"123")
                 self.assertEqual(sock.recv(3), b"123")
