patch 8.2.2413: crash when using :all while using a cmdline window

Problem:    Crash when using :all while using a cmdline window. (Zdenek Dohnal)
Solution:   Disallow :all from the cmdline window.
diff --git a/src/testdir/test_arglist.vim b/src/testdir/test_arglist.vim
index d6c369f..b72fe2d 100644
--- a/src/testdir/test_arglist.vim
+++ b/src/testdir/test_arglist.vim
@@ -559,4 +559,12 @@
   call delete('.c.swp')
 endfunc
 
+" Test for ":all" not working when in the cmdline window
+func Test_all_not_allowed_from_cmdwin()
+  au BufEnter * all
+  next x
+  call assert_fails(":norm 7q?x\<CR>", 'E11:')
+  au! BufEnter
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab