[Pytorch Mobile] Expose _export_operator_list to python (#51312)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51312
Follow up to D24690094 (https://github.com/pytorch/pytorch/commit/4a870f6518d3028293f48570ab57a8a4ad5c90e6) exposing the api in python. Created matching unit test.
ghstack-source-id: 120611452
Test Plan: Ran unit test
Reviewed By: dhruvbird
Differential Revision: D26112765
fbshipit-source-id: ffe3bb97de0a4f08b31719b4b47dcebd7d2fd42a
