Muon validation - get rid of spike in the entry /exit plots

Hi,

many muon validation plots show these strange spikes at roughly 180:

This spike is an artifact of setting the default value of the position/ momentum to -99999, if the corresponding extrapolation layer is not found. If we set the value to -1, the spike should show up at 0.002. Additionally, I introduced flags telling whether the truth matching at a given point & the extrapolation succeeded. If @pmogg, @atsiamis open a follow-up MR to not fill the corresponding histograms, if one of the flag is false. Then the spike above will disappear as well as the one below

Tagging: @pmogg, @atsiamis, @gabarone, @mvanadia