Polluting QuerySetBase::mQueryAvailability at encode time via a
phantom (never-submitted) encoder, then submitting a resolve-only encoder.
The D3D12 backend reads the polluted shared availability vector at submit time,
decides every slot is "available", and calls
ID3D12GraphicsCommandList::ResolveQueryData on a query heap that has
never had BeginQuery/EndQuery recorded against it in any
submitted command list — explicitly acknowledged as D3D12 undefined behaviour in
Dawn's own source comment.