Extend jit::load to work on flatbuffer file (#75022)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75022
Extending torch::jit::load to read flatbuffer file
ghstack-source-id: 152820697
Test Plan: CI
Reviewed By: iseeyuan
Differential Revision: D35060736
fbshipit-source-id: d653a5af662a46107ff4fd70209fd2a0a4d40f20
(cherry picked from commit 109e14a54bd279011c8f9066e6c29e8e0b1fc4db)
