bug#64846: Emacs 29 RC on Windows: White background color flashes on startup, before background color from config takes effect on Windows

[Eli Zaretskii]

> From: Yanchi Tóth <yanchi.toth@gmail.com>
> Date: Tue, 25 Jul 2023 10:56:31 +0200
> 
> White background color flashes on startup, before background color from
> config takes effect in parts of the rectangle occupied by Emacs. Didn't
> happen on 28.2, but does happen on both this RC, and the other 29
> pretests. See video attachment, and please let me know if I can be of any 
> help.

Please show a minimal init file that can be used to reproduce this
behavior.

Thanks.