BBSIM-ONU does not reach omci-flows-pushed after power-cycle in ATT scenario

After ten successful runs in a row, all runs of the test case PowerOffPowerOnONUDevice in the ATT scenario now go wrong in job https://jenkins.opencord.org/view/All%20Jobs/job/periodic-voltha-multiple-olts-openonu-go-test-bbsim/801/. The ONU adapter won't be called for delete-tcont and delete-gem-port during ONU power-off. In addition, the same call of update-flows-incrementally for deleting the default EAPOL-flow occurs three times. After the power-on the calls of download-tech-profile and update-flows-incrementally are missing for the EAPOL flow setup.