Add system tests for ISIS indirect diffraction. Refs #6733

Note that the separate OSIRIS test has been merged in to the common file.
Update LoadVesuvioTest along with LoadVesuvio changes. Refs #6733
Fix Vesuvio system test for parameter name changes. Refs #6733

No one is using this algorithm properly yet so the changes are managable.
Merge remote-tracking branch 'origin/feature/6733_vesuvio_diffraction'