C++ API parity: ELU, Hardshrink, Hardtanh, LeakyReLU, LogSigmoid minor fixes
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/27565
Test Plan: Imported from OSS
Differential Revision: D17835416
Pulled By: pbelevich
fbshipit-source-id: 9e83bdb4bf44cbc2ef09e2088df4bf0694c235f0
