Fix empty tensor handling in RReLU (#70496)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/70489
Add handling if `numel == 0`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70496
Reviewed By: zou3519, cpuhrsch
Differential Revision: D34286069
Pulled By: jbschlosser
fbshipit-source-id: a63797fe1ea05e5a192bc8e43327949b36ceebf2
(cherry picked from commit b410abe85e6554406550ed5cb36ffbc417214d66)
