add copy_ operator the op bench (#31327)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31327
Adds copy_ operator to the benchmark suite
Test Plan:
```
buck run caffe2/benchmarks/operator_benchmark/pt:binary_test -- --iterations 1 --operators copy_
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short
# Benchmarking PyTorch: copy_
# Mode: Eager
# Name: copy__M1_N1_K1_cpu_dtype_onetorch.int32_dtype_twotorch.int32
# Input: M: 1, N: 1, K: 1, device: cpu, dtype_one: torch.int32, dtype_two: torch.int32
Forward Execution Time (us) : 60.645
Reviewed By: hl475
Differential Revision: D19122910
fbshipit-source-id: e5f0b0e2612daae0201b1b4a87f52b971e0cc4a8
