Be more diligent about removing type variables in monomorphiser.
Be more diligent about removing type variables in monomorphiser.

diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark,HIPERFIT/futhark