tests/sort: simplify input to helper
tests/sort: simplify input to helper

wimh/coreutils,wimh/coreutils,kevgeniy/coreutils,jbcrail/coreutils,tempbottle/coreutils,keunwoo/coreutils,kwantam/coreutils,Arcterus/coreutils,tempbottle/coreutils,jbcrail/coreutils,ebfe/coreutils,kwantam/coreutils,ebfe/coreutils,uutils/coreutils,keunwoo/coreutils,Heather/coreutils,uutils/coreutils,uutils/coreutils,Heather/coreutils,Arcterus/coreutils,kevgeniy/coreutils