ddraw/tests: Skip some tests when switching the display mode is not supported.

[Francois Gouget]

On Mon, 17 Feb 2014, Henri Verbeet wrote:

> On 17 February 2014 17:45, Francois Gouget <fgouget at codeweavers.com> wrote:
> > This can happen on Windows 8 when the 'Microsoft Basic Display Adapter' driver does not recognize the graphics card, for instance QEmu's 'vga' graphics card.
> 
> As mentioned earlier on IRC, I think that setup is broken for the
> purpose of running the tests.

Yes, I will tweak the configuration of these two VMs. But I think the 
patch still makes sense.

The API behaves in a sane and rational way: some functionality is not 
supported so it returns E_NOTIMPL. That's something our tests should be 
able to handle.

-- 
Francois Gouget <fgouget at codeweavers.com>