Simplify map(reshape) into just reshape.
Simplify map(reshape) into just reshape.

Related to #520.

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