fix torch square_ benchmark runtime error (#31221)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31221
This is fixing the runtime error introduced in https://github.com/pytorch/pytorch/pull/30719 that added torch square_ operator to the benchmark suite.
Test Plan:
```
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short
# Benchmarking PyTorch: square_
# Mode: Eager
# Name: square__M512_N512_cpu
# Input: M: 512, N: 512, device: cpu
Forward Execution Time (us) : 66.291
Reviewed By: hl475
Differential Revision: D18987889
fbshipit-source-id: 09c56e3a73aab5ab661aac2b06429063b3a82fac
