Remove "prims_nvfuser" backend for TorchDynamo (#88083)
Removing "prims_nvfuser" backend according to the discussion in https://github.com/pytorch/torchdynamo/pull/1281#discussion_r979468355.
cc @mlazos @soumith @voznesenskym @yanboliang @penguinwu @anijain2305 @EikanWang @jgong5 @Guobing-Chen @chunyuan-w @XiaobingSuper @zhuhaozhe @blzheng @Xia-Weiwen @wenzhe-nrv @jiayisunx
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88083
Approved by: https://github.com/ezyang
