Remove use_c10_dispatcher option (#54969)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54969
With all use cases to hacky wrapper removed, all kernels will be
dispatched with c10 full dispatcher.
ghstack-source-id: 125434790
Test Plan: buck build //caffe2/aten/...
Reviewed By: ezyang, walterddr
Differential Revision: D27436596
fbshipit-source-id: 7a146d1f4a983b4a81f8552be4eec6c482b6bea2
