[Futurev4] fix failing tests

• Test 1: GaussSys.gausssys Here, I had to change the test so that it accepts the minimum working configuration coming from Gaussino.
• Test 2: LoKiGen.jira_461 ROOTIO from HepMC3 caused namespace collision with HepMC. It'll be now commented out in Gaussino as there is no need for it yet.
• Test 3: LoKiGen.lokigen0 Same problem as above + it looks like LoKi has some problems with dereferencing HepMC.GenParticle(). For example, this GP(HepMC.GenParticle()) gives

static double LoKi::Dicts::FunCalls<HepMC3::GenParticle>::__call__(LoKi::Functor<shared_ptr<const HepMC3::GenParticle>,double>& fun, const shared_ptr<const HepMC3::GenParticle>& o) =>
    could not convert argument 2

• Test 4: GaussTracker.shortened_sensdet_name This test, in its current shape, won't work because the expected debug debug() << "Sens det shortened name " << name() << " -> " << detname << endmsg; has been moved to the construct() in GiGaMTG4SensDetFactory. I wonder, in fact, whether this test is going to be useful... update: This is a very specific configuration in order to trigger a debug message with a shortened name of the sensitive detector. In order to do so, in Gauss-on-Gaussino it will only be triggered by running construct() on the GiGaSensDetTracker.

needs Gaussino/Gaussino!18 (merged) @gcorti @dmuller