[TensorExpr] rfactor implementation (#36237)
Summary:
A similar interface to Halide's rfactor: https://halide-lang.org/tutorials/tutorial_lesson_18_parallel_associative_reductions.html
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36237
Reviewed By: zheng-xq
Differential Revision: D21233309
Pulled By: bwasti
fbshipit-source-id: d2706a9e90b707ee195e339f834ff4a54b63a256
