Fixing issues with JETM derivations in ART tests

Currently four JETM derivations are failing the ART tests: JETM3, JETM5, JETM7 and JETM15. This MR fixes the issues observed for JETM3 and JETM5. JETM7 and JETM15 are not being fixed here. JETM7 requires additional changes from the flavour tagging group because it uses b-tagging information in the skimming which is not supported at the moment due to the recent changes and the problems with JETM15 are currently investigated by the relevant experts.

JETM3: crashed due to files required in fJVT tool that are currently only available afs and not cvmfs. The tool is commented out for now until the tool is officially recommended and the files are on cvmfs / eos.

JETM5: Missed adding jetm5Seq in the previous MR when fixing b-tagging issues