Revert D23898398: [Mask R-CNN]Add Int8 AABB Generate proposals Op
Test Plan: revert-hammer
Differential Revision:
D23898398 (https://github.com/pytorch/pytorch/commit/714c7020eee18404c631d584bde89e42b91a5112)
Original commit changeset: fb5f6d6ed8a5
fbshipit-source-id: 05284ff4db6c05fff3f4a6bb80f665e87c0bf085
