Add get/set_num_interop_threads into torch.h include (#20659)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20659
ghimport-source-id: 4858d03a9f89c613f64901c3430a7b212f76eb95
Reviewed By: dzhulgakov
Differential Revision: D15399780
Pulled By: ilia-cher
fbshipit-source-id: c1c3cb628c5ee664468f9d181bcd76a5105a89fd
