gl_state: Remove VAO cache and tracking

src/video_core/renderer_opengl/utils.h

@@ -16,7 +16,7 @@ public:
     explicit VertexArrayPushBuffer();
     ~VertexArrayPushBuffer();
 
-    void Setup(GLuint vao_);
+    void Setup();
 
     void SetIndexBuffer(const GLuint* buffer);
 
@@ -28,7 +28,6 @@ public:
 private:
     struct Entry;
 
-    GLuint vao{};
     const GLuint* index_buffer{};
     std::vector<Entry> vertex_buffers;
 };