Crash when copying PF_Stencil format from the GPU to the CPU

This is a crash related to copying depth-stencil render targets to the CPU.
See linked UDN for more info.

1. See attached repro project
2. Compile and launch the editor
3. Play in editor. Observe the D3D12 validation error.

> [Inline Frame]
UnrealEditor-Core.dll!UE::Logging::Private::BasicFatalLog::__l2::<lambda>() Line 1090 C++
UnrealEditor-Core.dll!UE::Logging::Private::BasicFatalLog(const FLogCategoryBase &
Category, const UE::Logging::Private::FStaticBasicLogRecord * Log, ...) Line 1090 C++
UnrealEditor-D3D12RHI.dll!D3D12RHI::VerifyD3D12Result(HRESULT D3DResult,
const char * Code, const char * Filename, unsigned int Line, ID3D12Device * Device, FString
Message) Line 903 C++
[Inline Frame]
UnrealEditor-D3D12RHI.dll!D3DX12Residency::Close(D3DX12Residency::ResidencySet *
pSet) Line 155C++
[Inline Frame] UnrealEditor-D3D12RHI.dll!FD3D12CommandList::Close() Line 290
C++
UnrealEditor-D3D12RHI.dll!FD3D12ContextCommon::CloseCommandList() Line 326
C++
UnrealEditor-D3D12RHI.dll!FD3D12CommandContext::CloseCommandList() Line 340
C++
UnrealEditor-D3D12RHI.dll!FD3D12ContextCommon::FlushCommands(ED3D12FlushFlags
FlushFlags) Line 612 C++
UnrealEditor-D3D12RHI.dll!FD3D12Texture::Lock(FRHICommandListImmediate *
RHICmdList, unsigned int MipIndex, unsigned int ArrayIndex, EResourceLockMode
LockMode, unsigned int & DestStride, unsigned __int64 * OutLockedByteCount) Line 1870
C++
UnrealEditor-D3D12RHI.dll!FD3D12DynamicRHI::LockTexture2D_RenderThread(FRHIComm
andListImmediate & RHICmdList, FRHITexture * TextureRHI, unsigned int MipIndex,
EResourceLockMode LockMode, unsigned int & DestStride, bool bLockWithinMiptail, bool
bNeedsDefaultRHIFlush, unsigned __int64 * OutLockedByteCount) Line 2200 C++
[Inline Frame]
UnrealEditor-DepthTest.dll!FRHICommandListImmediate::LockTexture2D(FRHITexture *) Line
4363 C++
[Inline Frame] UnrealEditor-DepthTest.dll!RHILockTexture2D(FRHITexture *) Line
5308 C++
[Inline Frame]
UnrealEditor-DepthTest.dll!FMySystem::PostOpaque::__l2::<lambda>(FRHICommandListImm
ediate &) Line 26 C++
[Inline Frame]
UnrealEditor-DepthTest.dll!TRDGLambdaPass<FEmptyShaderParameters,void
<lambda>(FRHICommandListImmediate
&)>::ExecuteLambdaFunc(FRHIComputeCommandList &) Line 607 C++
UnrealEditor-DepthTest.dll!TRDGLambdaPass<FEmptyShaderParameters,void
<lambda>(FRHICommandListImmediate &)>::Execute(FRHIComputeCommandList &
RHICmdList) Line 616 C++
UnrealEditor-RenderCore.dll!FRDGBuilder::ExecutePass(FRDGPass * Pass,
FRHIComputeCommandList & RHICmdListPass) Line 2917 C++
UnrealEditor-RenderCore.dll!FRDGBuilder::Execute() Line 1923 C++
UnrealEditor-Renderer.dll!RenderViewFamilies_RenderThread(FRHICommandListImmediate
& RHICmdList, const TArray<FSceneRenderer *,TSizedDefaultAllocator<32>> &
SceneRenderers) Line 4578 C++
 
UnrealEditor-Renderer.dll!FRendererModule::BeginRenderingViewFamilies::_l87::<lambda
3>::operator()(FRHICommandListImmediate & RHICmdList) Line 4848 C++
UnrealEditor-Renderer.dll!TEnqueueUniqueRenderCommandType<`FRendererModule::Begin
RenderingViewFamilies'::`87'::FDrawSceneCommandName,`FRendererModule::BeginRender
ingViewFamilies'::`87'::<lambda_3>>::DoTask(ENamedThreads::Type CurrentThread, const
TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 209 C++
UnrealEditor-Renderer.dll!TGraphTask<TEnqueueUniqueRenderCommandType<`FRenderer
Module::BeginRenderingViewFamilies'::`87'::FDrawSceneCommandName,`FRendererModule
::BeginRenderingViewFamilies'::`87'::<lambda_3>>>::ExecuteTask(TArray<FBaseGraphTask
*,TSizedDefaultAllocator<32>> & NewTasks, ENamedThreads::Type CurrentThread, bool
bDeleteOnCompletion) Line 1265 C++
[Inline Frame]
UnrealEditor-Core.dll!FBaseGraphTask::Execute(TArray<FBaseGraphTask
*,TSizedDefaultAllocator<32>> & CurrentThread, ENamedThreads::Type) Line 866 C++
UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread(int
QueueIndex, bool bAllowStall) Line 758 C++
UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex)
Line 649 C++
UnrealEditor-RenderCore.dll!RenderingThreadMain(FEvent *
TaskGraphBoundSyncEvent) Line 411 C++
UnrealEditor-RenderCore.dll!FRenderingThread::Run() Line 564 C++
UnrealEditor-Core.dll!FRunnableThreadWin::Run() Line 149 C++
UnrealEditor-Core.dll!FRunnableThreadWin::GuardedRun() Line 71 C++