Fix one failing CPU test in the full chain
One test is failing in the CPU run in the full Allen CI:
https://gitlab.cern.ch/lhcb/Allen/-/jobs/29015043#L263
The failure is likely due to a wrong naming of a folder, as the following is reported:
Build folder does not exist at build_x86_64_v3-el9-gcc12-dbg_all_BUILD_TESTING+ENABLE_CONTRACTS+TREAT_WARNINGS_AS_ERRORS ...