TEST: Remove duplicate QB_Toulouse_Ortho_PAN_mask.tif

There's already a QB_Toulouse_Ortho_PAN_Mask.tif used by other tests. See otb!158 (comment 70280).

I checked with find . | tr '[A-Z]' '[a-z]' | sort | uniq -c | grep -v " 1 ", and there seems to be no other instance of this actually there's a duplicate directory. One of them has a Input/Radiometry/Formosat2/formosat2.txt file, but I can't find any references to it.