Remove outputs of turbospruce throughput test

The Moore_turbospruce test occasionally breaks with

TFile::TFile                          ERROR file /home/lblocal/lhcb-ci/workspace/lhcb-pr-test/data/output/turbospruce_2025.b2oc.dst already exists

So to @dpopov suggested explicitly removing the outputs generated by the test, and further checking prior to running the test whether the outputs already exists due to some prior job failing.