Add op benchmark for batch box cox as baseline (#47275)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47275
```
# Benchmarking Caffe2: batch_box_cox
# Name: batch_box_cox_M64_N64_dtypedouble
# Input: M: 64, N: 64, dtype: double
Forward Execution Time (us) : 49.005
```
Test Plan: `buck run mode/opt caffe2/benchmarks/operator_benchmark/c2:batch_box_cox_test -- --iterations=1000 --warmup 100`
Reviewed By: houseroad
Differential Revision: D24675426
fbshipit-source-id: 8bb1f3076dc6b01e7b63468136ddf3d9b6d7e5d2
