Try to build the Docker image if it doesn't exist (#102562)
There is a bug in the test workflow where it could fail to find the new Docker image when the image hasn't yet became available on ECR, for example https://hud.pytorch.org/pytorch/pytorch/commit/e71ab214226af1f9dbded944e939c6447e0e8f09. This basically is a race condition where the test job starts before the docker-build workflow could finish successfully. The fix here is to make sure that the test job has the opportunity to build the image if it doesn't exist, same as what the build workflow does atm. Once the docker-build workflow finishes pushing the new image to ECR, that can then be used instead.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102562
Approved by: https://github.com/PaliC
