[BE] Use reusable workflows from test-infra (#86035)
Instead of local copies, use workflows checked into test-infra by https://github.com/pytorch/test-infra/pull/783
Thought about deleting the actions later, but if I understand how GHA merges work, older PRs merged onto this changes should not cause any problems as it will immediately reference actions from test-infra
Pull Request resolved: https://github.com/pytorch/pytorch/pull/86035
Approved by: https://github.com/kit1980
