Remove unnecessary doctest __main__ methods.

python/pyspark/accumulators.py

@@ -196,12 +196,3 @@ def _start_update_server():
     thread.daemon = True
     thread.start()
     return server
-
-
-def _test():
-    import doctest
-    doctest.testmod()
-
-
-if __name__ == "__main__":
-    _test()

python/pyspark/broadcast.py

@@ -37,12 +37,3 @@ class Broadcast(object):
     def __reduce__(self):
         self._pickle_registry.add(self)
         return (_from_id, (self.bid, ))
-
-
-def _test():
-    import doctest
-    doctest.testmod()
-
-
-if __name__ == "__main__":
-    _test()