[BE] Migration of Builder Repository to pytorch/pytorch and pytorch/test-infra repository

Our Nightly and Release pipeline spread over 3 repositories: pytorch/pytorch, pytorch/builder and pytorch/test-infra .This creates maintenance overhead and following issues: - Builder Repo Changes are not getting tested by PyTorch CI on PR. To test these changes developer need to open special PR against Pytorch/Pytorch poining to his builder fork. This makes it extremely difficult to test changes to builder repo - Changes to Docker builds can't be tested. - During Pytorch Release process we perform branch cut and cherry-picking to builder repo, not only pytorch/pytorch Hence to solve these issues we are working on Moving all Build and Test Scripts for pytorch binary to pytorch/pytorch All Validation and analytics scripts to pytorch/test-infra repository. Following Work Has been Completed: - [ ] Move Magma builds f https://github.com/pytorch/pytorch/issues/138909 https://github.com/pytorch/pytorch/pull/139924 https://github.com/pytorch/pytorch/issues/138909