patch 9.0.1087: autocommand test sometimes fails

Problem:    Autocommand test sometimes fails.
Solution:   Add a short delay. (James McCoy, closes #11737)
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index cf3d6fc..c6abb1b 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -2393,6 +2393,7 @@
   call term_sendkeys(buf, ":autocmd User\<CR>")
   call TermWait(buf, 50)
   call term_sendkeys(buf, "G")
+  call TermWait(buf, 50)
 
   call StopVimInTerminal(buf)
 endfunc