GPU: Move graphics API reset state to System

Stops us trying to reset state on objects which don't exist if
initialization failed (apparently some Android devices.. of course).

src/core/gpu_hw_d3d11.cpp

@@ -19,7 +19,6 @@ GPU_HW_D3D11::GPU_HW_D3D11(ID3D11Device* device, ID3D11DeviceContext* context) :
 GPU_HW_D3D11::~GPU_HW_D3D11()
 {
   g_host_display->ClearDisplayTexture();
-  GPU_HW_D3D11::ResetGraphicsAPIState();
 
   DestroyShaders();
   DestroyStateObjects();

src/core/gpu_hw_d3d12.cpp

@@ -22,7 +22,6 @@ GPU_HW_D3D12::GPU_HW_D3D12() = default;
 GPU_HW_D3D12::~GPU_HW_D3D12()
 {
   g_host_display->ClearDisplayTexture();
-  GPU_HW_D3D12::ResetGraphicsAPIState();
 
   DestroyResources();
 }

src/core/gpu_hw_opengl.cpp

@@ -29,7 +29,6 @@ GPU_HW_OpenGL::~GPU_HW_OpenGL()
     glDeleteTextures(1, &m_texture_buffer_r16ui_texture);
 
   g_host_display->ClearDisplayTexture();
-  GPU_HW_OpenGL::ResetGraphicsAPIState();
 
   // One of our programs might've been bound.
   GL::Program::ResetLastProgram();

src/core/gpu_hw_vulkan.cpp

@@ -21,7 +21,6 @@ GPU_HW_Vulkan::GPU_HW_Vulkan() = default;
 GPU_HW_Vulkan::~GPU_HW_Vulkan()
 {
   g_host_display->ClearDisplayTexture();
-  GPU_HW_Vulkan::ResetGraphicsAPIState();
   DestroyResources();
 }
 

src/core/system.cpp

@@ -1477,6 +1477,8 @@ void System::DestroySystem()
   Timers::Shutdown();
   Pad::Shutdown();
   CDROM::Shutdown();
+  if (g_gpu)
+    g_gpu->ResetGraphicsAPIState();
   g_gpu.reset();
   InterruptController::Shutdown();
   DMA::Shutdown();