Make several methods of SharedParserData private (#66670)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/66670
Reviewed By: zhxchen17
Differential Revision: D31674377
Pulled By: gmagogsfm
fbshipit-source-id: 5c73b78f842c5c4305047ca98f40bf99bd3d2d60
