patch 8.2.1768: cannot use the help menu from a terminal window

Problem:    Cannot use the help menu from a terminal window.
Solution:   Add ":tlnoremenu" commands. (Yee Cheng Chin, closes #7023)
diff --git a/src/testdir/test_gui.vim b/src/testdir/test_gui.vim
index 64537ac..89ec3a9 100644
--- a/src/testdir/test_gui.vim
+++ b/src/testdir/test_gui.vim
@@ -739,6 +739,9 @@
 
   " Check deleting menu doesn't cause trouble.
   aunmenu Help
+  if exists(':tlmenu')
+    tlunmenu Help
+  endif
   call assert_fails('menu Help', 'E329:')
 endfunc