Add simplification rule for indexing result of a trivial reshape.
Add simplification rule for indexing result of a trivial reshape.

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