patch 8.0.1271: still too many old style tests

Problem:    Still too many old style tests.
Solution:   Convert a few more tests to new style. (Yegappan Lakshmanan,
            closes #2290)
diff --git a/src/testdir/sautest/autoload/footest.vim b/src/testdir/sautest/autoload/footest.vim
index f467bc3..1e78963 100644
--- a/src/testdir/sautest/autoload/footest.vim
+++ b/src/testdir/sautest/autoload/footest.vim
@@ -1,4 +1,4 @@
-" Autoload script used by test55 and test60
+" Autoload script used by test_listdict.vim, test_exists.vim and test_let.vim
 let footest#x = 1
 func footest#F()
   return 0