Remove last use of LS_PROGRAM

Globs are not determined by an `eval` of `ls` anymore. The only other
use of `ls` can be replaced with a simple `printf`.

test/003_unit_ls_program.bats

@@ -1,66 +0,0 @@
-load common
-load_fixtures
-
-@test "Default /bin/ls" {
-  echo "
-    By default, the value of LS_PROGRAM should be /bin/ls
-  "
-
-  # shellcheck source=/dev/null
-  YADM_TEST=1 source "$T_YADM"
-  status=0
-  output=$( require_ls; echo "$LS_PROGRAM" ) || {
-    status=$?
-    true
-  }
-
-  echo "output=$output"
-
-  [ "$status" == 0 ]
-  [ "$output" = "/bin/ls" ]
-}
-
-@test "Fallback on 'ls'" {
-  echo "
-    When LS_PROGRAM doesn't exist, use 'ls'
-  "
-
-  # shellcheck source=/dev/null
-  YADM_TEST=1 source "$T_YADM"
-  status=0
-  LS_PROGRAM="/ls/missing"
-  output=$( require_ls; echo "$LS_PROGRAM" ) || {
-    status=$?
-    true
-  }
-
-  echo "output=$output"
-
-  [ "$status" == 0 ]
-  [ "$output" = "ls" ]
-}
-
-@test "Fail if ls isn't in PATH" {
-  echo "
-    When LS_PROGRAM doesn't exist, use 'ls'
-  "
-
-  # shellcheck source=/dev/null
-  YADM_TEST=1 source "$T_YADM"
-  status=0
-  LS_PROGRAM="/ls/missing"
-  savepath="$PATH"
-  # shellcheck disable=SC2123
-  PATH=
-  output=$( require_ls 2>&1; echo "$LS_PROGRAM" ) || {
-    status=$?
-    true
-  }
-  PATH="$savepath"
-
-  echo "output=$output"
-
-  [ "$status" != 0 ]
-  [[ "$output" =~ functionality\ requires\ .ls.\ to\ be\ installed ]]
-}
-