test(backend): prepares a test/presubmit-backend-test.sh script. Part of #3436 (#4220)
test(backend): prepares a test/presubmit-backend-test.sh script. Part of #3436 (#4220)

* test(backend): prepares a hack/run_unit_tests_backend.sh script

* Move test script location
kubeflow/pipelines,kubeflow/pipelines,kubeflow/pipelines,kubeflow/pipelines,kubeflow/pipelines,kubeflow/pipelines