labelsgmfix: Upsample T1 if low-resolution
labelsgmfix: Upsample T1 if low-resolution

A similar heurisstic was implemented for 5ttgen fsl previously.

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3