Set up a periodic job for openshift/origin, running one of the pre-defined build tests.

This can be done by adding the `cron` option to one of the build job configurations in openshift/release for the openshift/origin repo.

See also:

• CI Operator step reference: https://steps.ci.openshift.org/ci-operator-reference#line552
• CI operator arch doc: https://docs.ci.openshift.org/docs/architecture/ci-operator/
• openshift/origin config for "master" branch: https://github.com/openshift/release/blob/master/ci-operator/config/openshift/origin/openshift-origin-master.yaml