bpo-28533: Remove asyncore, asynchat, smtpd modules (GH-29521)

Remove the asyncore and asynchat modules, deprecated in Python
3.6: use the asyncio module instead.

Remove the smtpd module, deprecated in Python 3.6: the aiosmtpd
module can be used instead, it is based on asyncio.

* Remove asyncore, asynchat and smtpd documentation
* Remove test_asyncore, test_asynchat and test_smtpd
* Rename Lib/asynchat.py to Lib/test/support/_asynchat.py
* Rename Lib/asyncore.py to Lib/test/support/_asyncore.py
* Rename Lib/smtpd.py to Lib/test/support/_smtpd.py
* Remove DeprecationWarning from private _asyncore, _asynchat and
  _smtpd modules
* _smtpd: remove deprecated properties

1 files changed, 3 insertions, 7 deletions

diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 56e3d8a..c9edfac 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -18,17 +18,13 @@ except ImportError:
 
 from unittest import TestCase, skipUnless
 from test import support
-from test.support import threading_helper
+from test.support import _asynchat as asynchat
+from test.support import _asyncore as asyncore
 from test.support import socket_helper
+from test.support import threading_helper
 from test.support import warnings_helper
 from test.support.socket_helper import HOST, HOSTv6
 
-import warnings
-with warnings.catch_warnings():
-    warnings.simplefilter('ignore', DeprecationWarning)
-    import asyncore
-    import asynchat
-
 
 TIMEOUT = support.LOOPBACK_TIMEOUT
 DEFAULT_ENCODING = 'utf-8'