Remove circular imports hack in multiprocessing

Lib/multiprocessing/reduction.py

@@ -16,10 +16,7 @@ import pickle
 import socket
 import sys
 
-# XXX RustPython TODO: figure out why this doesn't work
-# from . import context
-from .context import *
-context = sys.modules[__name__]
+from . import context
 
 __all__ = ['send_handle', 'recv_handle', 'ForkingPickler', 'register', 'dump']