Fix the two system tests. The Aziz one just has a new reference result as the internal order of the grouped detectors has changed but this should not matter since we don't ungroup afterward. The TOSCA test failed because ExtractSingleSpectrum was pulling out the incorrect spectrum after the ISpectra changes. The blame here is due to a bad unit test, it only tested the data and not the underlying spectra/detector links. This test has been improved. Refs #3203