Remove Import.alias_name_part, it was simply an alias for another lookup.

jedi/parser/representation.py

@@ -861,14 +861,6 @@ class Import(Simple):
             n.append(self.alias)
         return n
 
-    @property
-    def alias_name_part(self):
-        """
-        TODO refactor and dont use this method, because NamePart will not exist in
-          the future.
-        """
-        return self.alias
-
     def is_nested(self):
         """
         This checks for the special case of nested imports, without aliases and