Add test where in-place updates could not be lowered.
Add test where in-place updates could not be lowered.

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