message: dx12: Handle present texture in a specially
  PRESENT is an exclusive flag in NXT and can't be combined with other flags. The existing implementation treats the D3D12_RESOURCE_STATE_PRESENT as flag which is confusing due to being 0.
diff: @@ -24,6 +24,11 @@ namespace backend { namespace d3d12 {
  nxt::TextureFormat format) {
  D3D12_RESOURCE_STATES resourceState = D3D12_RESOURCE_STATE_COMMON;
  + // Present is an exclusive flag.
  + if (usage & nxt::TextureUsageBit::Present) {
  + return D3D12_RESOURCE_STATE_PRESENT;
  + }
  +
  if (usage & nxt::TextureUsageBit::TransferSrc) {
  resourceState |= D3D12_RESOURCE_STATE_COPY_SOURCE;
  }
  @@ -44,9 +49,6 @@ namespace backend { namespace d3d12 {
  resourceState |= D3D12_RESOURCE_STATE_RENDER_TARGET;
  }
  }
  - if (usage & nxt::TextureUsageBit::Present) {
  - resourceState |= D3D12_RESOURCE_STATE_PRESENT;
  - }
  return resourceState;
  }
  