Fix first-order transformation of redomap.
Fix first-order transformation of redomap.

diku-dk/futhark,diku-dk/futhark,ihc/futhark,mrakgr/futhark,ihc/futhark,ihc/futhark,HIPERFIT/futhark,mrakgr/futhark,mrakgr/futhark,HIPERFIT/futhark,CulpaBS/wbBach,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark