This added check is in line with two other checks just a few lines below.
No, those calls can actually fail without failing tests. This one can't.
and creating swapchain can fail outside winetest's control (e.g. because of an unsuitable driver, etc.). so a fail here doesn't (necessarily) mean a bug in wine.
Can it? Do you have evidence of this happening?
If it can, then we need to change the test itself, and at that point of course we would exit early. But at the moment it seems that if it's possible to create a device, then that CreateSwapchain() call should also succeed.