patch 8.2.0270: some code not covered by tests

Problem:    Some code not covered by tests.
Solution:   Add test cases. (Yegappan Lakshmanan, closes #5649)
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 23deec6..3b07104 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -2357,3 +2357,5 @@
   au! crash
   setglobal spellfile=
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab