reduce conv_test input shapes (#29580)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29580
The input shapes of Conv benchmark generates too many tests which could took 40+GB memory. This diff reduces the input shapes to fix that issue.
Test Plan:
```
buck run //caffe2/benchmarks/operator_benchmark/pt:conv_test -- --iteration 1
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short
# Benchmarking PyTorch: Conv3d
# Mode: Eager
# Name: Conv3d_in_c64_out_c64_kernel3_stride1_N8_D4_H16_W16_cpu
# Input: in_c: 64, out_c: 64, kernel: 3, stride: 1, N: 8, D: 4, H: 16, W: 16, device: cpu
Forward Execution Time (us) : 383376.096
Reviewed By: hl475
Differential Revision: D18434627
fbshipit-source-id: a91a239394b034ff7b42e1b09e2f744a8ad671e9
