gdiplus: Use outside color from image attributes for an out of bounds pixel.

[Vincent Povirk]

>                      if (src_pointf.X >= srcx && src_pointf.X < srcx + srcwidth && src_pointf.Y >= srcy && src_pointf.Y < srcy+srcheight)
>                          *dst_color = resample_bitmap_pixel(&src_area, src_data, bitmap->width, bitmap->height, &src_pointf, imageAttributes, interpolation);
>                      else
> -                        *dst_color = 0;
> +                        *dst_color = imageAttributes->outside_color;

It's like this for a reason. This isn't out of the bounds of the
source image, which is when imageAttributes would apply. This is out
of the bounds of the parallelogram we're drawing, and we should be
leaving that pixel alone.