vim-patch:9.1.0990: Inconsistent behavior when changing cmdheight (#31830)

Problem:  Inconsistent behavior when changing cmdheight by resizing the
          topframe through wincmds and dragging laststatus. Changing
          cmdheight by resizing the topframe does not trigger OptionSet.
Solution: Consolidate logic for changing the cmdheight, set the option
          value to handle side-effects (Luuk van Baal)

e15cbc1af4

vim-patch:9.0.0187: command line height changes when maximizing window height

Problem:  Command line height changes when maximizing window height.
Solution: Do not change the command line height. (closes vim/vim#10885)

96bde99bf8

test/functional/legacy/window_cmd_spec.lua

@@ -299,7 +299,7 @@ describe('splitkeep', function()
       c                                                    |
       {1:~                                                    }|
       {3:[No Name]                                            }|
-                                                           |
+      :call win_move_statusline(win, 1)                    |
     ]])
   end)