Set quantized engine backend for mobile in speed_benchmark_torch (#26911)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26911
Check if QNNPACK is present as a backend (should always be present on mobile).
If it is present then set the backend to QNNPACK
Test Plan:
Test on mobile
./speed_benchmark_torch --model mobilenet_quantized_scripted.pt --input_dims="1,3,224,224" --input_type=float --warmup=5 --iter 20 --print_output True
Imported from OSS
Differential Revision: D17613908
fbshipit-source-id: af96722570a0111f13d69c38ccca52416ea5e460
