Fix DXGI implicit backbuffer index tracking
Fix DXGI implicit backbuffer index tracking

* When DXGI_PRESENT_TEST flag is present, the backbuffer index doesn't
  increment.
* Resizing the buffers resets the index back to 0.

Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,baldurk/renderdoc