get Results_Table.txt and RMSResults.root files from output/MSCTest subdirectory

GeantTestEm5Handle looks for the results files in the output whereas they are in MSCTest subdirectory. This is why there was no results in lhcbpr for this job. See e.g. https://jenkins-lhcb-nightlies.web.cern.ch/job/nightly-builds/job/tests/144980//console and https://jenkins-lhcb-nightlies.web.cern.ch/job/nightly-builds/job/tests/144981//console