[3.15] gh-161336: fix host mismatch in the test_imaplib (GH-161349) (#161424)

gh-161336: fix host mismatch in the `test_imaplib` (GH-161349)
(cherry picked from commit 356e6e2)

Co-authored-by: Neko Asakura <neko.asakura@outlook.com>

Author: miss-islington

Lib/test/test_imaplib.py

@@ -740,9 +740,8 @@ def handle(self):
                 SimpleIMAPHandler.handle(self)
 
         _, server = self._setup(TimeoutHandler)
-        addr = server.server_address[1]
         with self.assertRaises(TimeoutError):
-            client = self.imap_class("localhost", addr, timeout=0.001)
+            client = self.imap_class(*server.server_address, timeout=0.001)
 
     def test_with_statement(self):
         _, server = self._setup(SimpleIMAPHandler, connect=False)