Made the MaintenanceInverseOffers test use only one framework.
Made the MaintenanceInverseOffers test use only one framework.

This patch simplifies the test and attepmts to fix MESOS-9980 by
removing the (potential) flakiness caused by agent2's resources
being re-offered to framework2.

Review: https://reviews.apache.org/r/71560/

kaysoky/mesos,dforsyth/mesos,kaysoky/mesos,reneploetz/mesos,abudnik/mesos,Gilbert88/mesos,dforsyth/mesos,abudnik/mesos,Gilbert88/mesos,dforsyth/mesos,reneploetz/mesos,kaysoky/mesos,kaysoky/mesos,kaysoky/mesos,reneploetz/mesos,abudnik/mesos,Gilbert88/mesos,kaysoky/mesos,dforsyth/mesos,reneploetz/mesos,dforsyth/mesos,abudnik/mesos,abudnik/mesos,Gilbert88/mesos,dforsyth/mesos,Gilbert88/mesos,abudnik/mesos,reneploetz/mesos,kaysoky/mesos,reneploetz/mesos,abudnik/mesos,reneploetz/mesos,Gilbert88/mesos,Gilbert88/mesos,dforsyth/mesos