Re #8338. Fix rarely-run system test.

The property type was changed to boolean in #8266.
Refs #8337 Add system test to check this use case.
Refs #7732 added .detcal to banned Regex in LoadLotsOfFiles

Another file that shouldn't be loaded was found, added .detcal to the banned list.

Re-added the .cal blanket ban after a merge from master overwrote it.
Merge branch 'feature/7732_Load_Save_Ascii_Multiple_Spectra' into develop