Having a __wine_display_device_guid property in the desktop window only guarantees that the window
is created. Explorer.exe still has to finish setting up virtual desktop, display settings etc.
load_desktop_driver() needs to make sure that the desktop initialization is done before allowing
applications to call user32 driver functions. Otherwise, they might get incorrect data. This race
condition became apparent after aadae4d1, which adds ~100ms to the
initialization process.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=49762Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>