Revert "Add a convenience function for blitting."
Revert "Add a convenience function for blitting."

This reverts commit a9e89f06181fd7719eb0467fd49d120ecd270b8d.

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