move generator test into ops folder to accelerate tests (#5472)

* move generator test into ops folder to accelerate tests

* ensure ONEFLOW_TEST_CPU_ONLY

* auto format by CI

Co-authored-by: oneflow-ci-bot <ci-bot@oneflow.org>
Co-authored-by: oneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>