GPU: Align presenter/backends to cache line

src/core/gpu_backend.h

@@ -27,7 +27,7 @@ struct MemorySaveState;
 // DESIGN NOTE: Only static methods should be called on the CPU thread.
 // You specifically don't have a global pointer available for this reason.
 
-class GPUBackend
+class ALIGN_TO_CACHE_LINE GPUBackend
 {
 public:
   static GPUThreadCommand* NewClearVRAMCommand();

src/core/gpu_presenter.h

@@ -23,7 +23,7 @@ struct GPUSettings;
 struct GPUBackendUpdateDisplayCommand;
 struct GPUBackendFramePresentationParameters;
 
-class GPUPresenter final
+class ALIGN_TO_CACHE_LINE GPUPresenter final
 {
 public:
   GPUPresenter();