Minor fixs to make torchbench runable on torch/xla (#107919)
`import torch_xla.core.xla_model as xm` no longer trigger the xla runtime to init, hence explictly create the device here. This is a workaround for https://github.com/pytorch/xla/issues/4174.
`is_correct` reference has been deleted, I think it is a deadcode.
After this patch, I am able to run
```
python benchmarks/dynamo/torchbench.py --randomize-input --performance --trace-on-xla --training --backend=openxla --only resnet50
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107919
Approved by: https://github.com/shunting314, https://github.com/wconstab
