vim-patch:8.2.1770: invalid memory use when using SpellFileMissing autocmd

Problem:    Invalid memory use when using SpellFileMissing autocmd.
Solution:   Add test case. (Dominique Pellé, closes vim/vim#7036)  Fix using a window
            that was closed.
d569a9e746

Skip an assert because of #3027.

src/nvim/spell.c

@@ -2327,11 +2327,11 @@ char *did_set_spelllang(win_T *wp)
       }
     }
   }
+  redraw_later(wp, NOT_VALID);
 
 theend:
   xfree(spl_copy);
   recursive = false;
-  redraw_later(wp, NOT_VALID);
   return ret_msg;
 }