Revert D25056091: migrate export_caffe2_op_to_c10.h macros to the new dispatcher registration API
Test Plan: revert-hammer
Differential Revision:
D25056091 (https://github.com/pytorch/pytorch/commit/0ea4982cf3ef68de655fa5a5597b44639e165207)
Original commit changeset: 0f647ab9bc5e
fbshipit-source-id: e54047b91d82df25460ee00482373c4580f94d50
