Refs #8514 removed quick script case for loaded in ADS or not

There was a section in the quick script that shouldn't have been there as it was doing different thigns depending if the ADS had a workspace or not.

It is now only using the case as if it wasn't in the ADS in order to avoid a Divide error.
Merge remote-tracking branch 'origin/feature/8514_Reflectometry_quick_system_test'