Remove legacy experimental jobs
Remove legacy experimental jobs

If projects are interested in these jobs, I think it's better they add
them in-repo these days.  Remove from the integrated-gate definition.

Change-Id: Icb0c3a1c07e7158de1edab97c94a5083106f4064

openstack-infra/openstack-zuul-jobs,openstack-infra/openstack-zuul-jobs