Revert D29330585: [pytorch][PR] add BFloat16 support for arange on CPU
Test Plan: revert-hammer
Differential Revision:
D29330585 (https://github.com/pytorch/pytorch/commit/375d2010867e32c15da6ef0d7bd151dea418ff29)
Original commit changeset: b8a04cee0c3f
fbshipit-source-id: dc138f9613becd083848e82d15c138d3883493c8
