gh-101225: Increase the socket backlog when creating a multiprocessing.connection.Listener (#113567)

Increase the backlog for multiprocessing.connection.Listener` objects created
 by `multiprocessing.manager` and `multiprocessing.resource_sharer` to
 significantly reduce the risk of getting a connection refused error when creating
 a `multiprocessing.connection.Connection` to them.

Lib/multiprocessing/managers.py

@@ -156,7 +156,7 @@ class Server(object):
         Listener, Client = listener_client[serializer]
 
         # do authentication later
-        self.listener = Listener(address=address, backlog=16)
+        self.listener = Listener(address=address, backlog=128)
         self.address = self.listener.address
 
         self.id_to_obj = {'0': (None, ())}