Remove pointless round-trip through SOAC.fromExp.
Remove pointless round-trip through SOAC.fromExp.

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