skip cuda test if not on GPU machines
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/29287
Test Plan:
```
buck run mode/dev-nosan //caffe2/benchmarks/operator_benchmark:benchmark_all_test -- --iterations 1
# ----------------------------------------
# PyTorch/Caffe2 Operator Micro-benchmarks
# ----------------------------------------
# Tag : short
# Benchmarking PyTorch: ConvTranspose2d
# Mode: Eager
# Name: ConvTranspose2d_kernel3_out_c256_H16_in_c256_N1_stride1_W16_cpu
# Input: kernel: 3, out_c: 256, H: 16, in_c: 256, N: 1, stride: 1, W: 16, device: cpu
Forward Execution Time (us) : 10434.151
Reviewed By: hl475
Differential Revision: D18344574
fbshipit-source-id: 881c857cf901c4539ee1a61171ab41df1c476db7
