Don't leak default created objects

Sometimes NXT provides default objects for parts of the pipelines, for
example a default pipeline layout. This objects were create with code
like: device->CreateFooBuilder()->GetResult(); and stored in a Ref<>.
This caused the object to have on external reference and two internal
references and not get destroyed when the Ref<> goes out. Call Release
on these objects to remove the external reference and fix the leak.

Was found via the Vulkan validation layers that were complaining that a
VkPipelineLayout was leaked.

src/backend/Pipeline.cpp

@@ -32,6 +32,8 @@ namespace backend {
                           ->GetDevice()
                           ->CreatePipelineLayoutBuilder()
                           ->GetResult();
+            // Remove the external ref objects are created with
+            mLayout->Release();
         }
 
         auto FillPushConstants = [](const ShaderModuleBase* module, PushConstantInfo* info) {

src/backend/RenderPipeline.cpp

@@ -89,9 +89,13 @@ namespace backend {
         // the device
         if (!mInputState) {
             mInputState = mDevice->CreateInputStateBuilder()->GetResult();
+            // Remove the external ref objects are created with
+            mInputState->Release();
         }
         if (!mDepthStencilState) {
             mDepthStencilState = mDevice->CreateDepthStencilStateBuilder()->GetResult();
+            // Remove the external ref objects are created with
+            mDepthStencilState->Release();
         }
         if (!mRenderPass) {
             HandleError("Pipeline render pass not set");
@@ -109,6 +113,8 @@ namespace backend {
         for (uint32_t attachmentSlot :
              IterateBitSet(subpassInfo.colorAttachmentsSet & ~mBlendStatesSet)) {
             mBlendStates[attachmentSlot] = mDevice->CreateBlendStateBuilder()->GetResult();
+            // Remove the external ref objects are created with
+            mBlendStates[attachmentSlot]->Release();
         }
 
         return mDevice->CreateRenderPipeline(this);