Fix execution of .qmt files

As already discussed in the DPA mattermost channel:

For debugging & development, it is really important to be able to quickly run a test as specified in a qmt file.
This works in all other projects via ./PROJECT/run gaudirun.py test.qmt.

DaVinci broke this behavior when introducing their new way of launching tests, and this remains broken with the move to lbexec.

IMHO it would be really nice if something like the below could be made to work:

./DaVinci/run lbexec DaVinciExamples/tests/qmtest/tupling.qms/test_davinci_tupling_from_hlt2.qmt