[jit] Clean up unneeded virtual methods from Function interface. (#65968)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65968
tryToGraphFunction() should cover all cases and more composable than
adhoc virtual methods.
ghstack-source-id: 141759214
Test Plan: no behavior change.
Reviewed By: gmagogsfm
Differential Revision: D31326154
fbshipit-source-id: 692a35df424f7d4f777a96489c4cbb24b3ae7807
