trunk/b262babb27246aa174c74289e5624b3ccfe7e3f5: Make the softshrink decompositions match eager bitwise (#200802)

发生了什么

The softshrink reference did not match the ATen kernels, which made softshrink fail Inductor's strict-numerics checks (and led #200768 to add Inductor-only special cases for it). Fix it at the decomposition layer instead: Match each backend's kernel on NaN and signed zeros. CUDA returns NaN as is and +0 in the dead zone; MPS computes a * 0 , which is -0.0 for negative inputs. The CPU kernel is not consistent with it…

摘要按规则整理自下方来源原文

来源