Testing shows that this affects behavior. Transforming a region turns
empty rectangles (with negative width or height) into non-empty
rectangles. If an empty rectangle is set, it's treated as non-empty
only when there is a world transform.
Signed-off-by: Vincent Povirk <vincent@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>