gdi32: Fixed GetDIBits for top-down bitmaps (try 2).

[Alexandre Julliard]

Jack Edmonds <pocketcookies2 at gmail.com> writes:

> gdi32/dib.c:          Reversed source bitmap pointer instead of destination bitmap pointer.
>                       Removed check for destination bitmap height when determining whether to copy the source bitmap upside down.
> gdi32/tests/bitmap.c: Added a test for copying between top-down bitmaps.

The rest of the code won't cope so well with a negative source
width.

-- 
Alexandre Julliard
julliard at winehq.org