The if condition here came from 47c54c4a,
which is to detect full screen window.

However, according to tests in previous commit, there is possibility
that a window without setting WS_CAPTION is not full screen, for example,
main window of Tencent WeChat. And windows like this can also be maximized
or restored. So that we can not treat WS_CAPTION as our full screen condition.

This fixes maximizing Tencent WeChat by dragging it to screen edge.
Signed-off-by: Ziqing Hui <zhui@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>