[dynamo] relax fake tensor restriction with `assume_constant_result` (#87895)
This works now because of https://github.com/pytorch/pytorch/pull/87091,
so don't error out anymore.
cc @jansel @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/87895
Approved by: https://github.com/tugsbayasgalan, https://github.com/voznesenskym
