Fix certificate usage in tuple transform of lambdas.
Fix certificate usage in tuple transform of lambdas.

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