Make sure not to leak any enabled vertex arrays.

When returning to EmuScreen, we need to reset any enabled vertex arrays or
we could crash in EmuScreen.  Also, when starting a frame / dirting the
shader, make sure also to toggle the vertex arrays.

Core/System.cpp

@@ -454,6 +454,8 @@ void PSP_RunLoopUntil(u64 globalticks) {
 	} else {
 		mipsr4k.RunLoopUntil(globalticks);
 	}
+
+	gpu->CleanupBeforeUI();
 }
 
 void PSP_RunLoopFor(int cycles) {

GPU/GLES/GLES_GPU.cpp

@@ -2104,6 +2104,11 @@ void GLES_GPU::ClearShaderCache() {
 	shaderManager_->ClearCache(true);
 }
 
+void GLES_GPU::CleanupBeforeUI() {
+	// Clear any enabled vertex arrays.
+	shaderManager_->DirtyLastShader();
+}
+
 std::vector<FramebufferInfo> GLES_GPU::GetFramebufferList() {
 	return framebufferManager_.GetFramebufferList();
 }

GPU/GLES/GLES_GPU.h

@@ -59,6 +59,7 @@ public:
 	// Called by the window system if the window size changed. This will be reflected in PSPCoreParam.pixel*.
 	virtual void Resized();
 	virtual void ClearShaderCache();
+	virtual void CleanupBeforeUI();
 	virtual bool DecodeTexture(u8* dest, GPUgstate state) {
 		return textureCache_.DecodeTexture(dest, state);
 	}

GPU/GLES/ShaderManager.cpp

@@ -662,7 +662,7 @@ void ShaderManager::DirtyShader() {
 	// Forget the last shader ID
 	lastFSID_.clear();
 	lastVSID_.clear();
-	lastShader_ = 0;
+	DirtyLastShader();
 	globalDirty_ = 0xFFFFFFFF;
 	shaderSwitchDirty_ = 0;
 }

GPU/GPUCommon.h

@@ -118,6 +118,7 @@ public:
 		return std::vector<FramebufferInfo>();
 	}
 	virtual void ClearShaderCache() {}
+	virtual void CleanupBeforeUI() {}
 
 protected:
 	// To avoid virtual calls to PreExecuteOp().

GPU/GPUInterface.h

@@ -269,6 +269,7 @@ public:
 	// Called by the window system if the window size changed. This will be reflected in PSPCoreParam.pixel*.
 	virtual void Resized() = 0;
 	virtual void ClearShaderCache() = 0;
+	virtual void CleanupBeforeUI() = 0;
 	virtual bool FramebufferDirty() = 0;
 	virtual bool FramebufferReallyDirty() = 0;
 	virtual bool BusyDrawing() = 0;