unify as_strided benchmark (#28890)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28890
as title
Test Plan:
```
buck run mode/opt //caffe2/benchmarks/operator_benchmark/pt:as_strided_test
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short
# Benchmarking PyTorch: as_strided
# Mode: Eager
# Name: as_strided_M256_N256_size(32,32)_stride(1,1)_storage_offset0_cpu
# Input: M: 256, N: 256, size: (32, 32), stride: (1, 1), storage_offset: 0, device: cpu
Forward Execution Time (us) : 2.792
...
Reviewed By: hl475
Differential Revision: D18227052
fbshipit-source-id: e17d9335ec89b47706a363bdb31451a01d4cbc5b
