Refactor tests for tfjob-controller

[tenzen-y]

Currently, we have many duplicated tests for the tfjob-controller, which are flaky.

For example, we have duplicated tests for Job:

• https://github.com/kubeflow/training-operator/blob/59cc98cbfc906546b096a29f5d31482fba7cdebf/pkg/controller.v1/tensorflow/job_test.go#L42
• https://github.com/kubeflow/training-operator/blob/59cc98cbfc906546b096a29f5d31482fba7cdebf/pkg/controller.v1/tensorflow/tfjob_controller_test.go#L32

So, we should refactor those tests and then implement tests like PyTorchJob:

https://github.com/kubeflow/training-operator/blob/59cc98cbfc906546b096a29f5d31482fba7cdebf/pkg/controller.v1/pytorch/pytorchjob_controller_test.go

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[tenzen-y]

/lifecycle frozen