d3d9/tests: Fix test for old gfx-card

[Michael Karcher]

Am Montag, den 13.10.2008, 15:03 +0200 schrieb Stefan Dösinger:
> It is kinda strange, since the NULLREF device should be device independent,
MSDN claims that NULLREF is the same as REF if the reference rasterizer
is installed. The reference rasterizer can not handle every framebuffer
format, most notably, packed 24 bpp true color (D3DFMT_R8G8B8) support
is missing, as most modern cards use 32 bpp true color
(D3DFMT_X8R8G8B8). I would expect NULLREF to fail on a system with
d3dref9.dll available but a 24 bpp framebuffer.

Regards,
  Michael Karcher