Add ClearAll to rasterizer cache for fully wiping the cache on save/load

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -1367,6 +1367,10 @@ void RasterizerOpenGL::FlushAndInvalidateRegion(PAddr addr, u32 size) {
     res_cache.InvalidateRegion(addr, size, nullptr);
 }
 
+void RasterizerOpenGL::ClearAll(bool flush) {
+    res_cache.ClearAll(flush);
+}
+
 bool RasterizerOpenGL::AccelerateDisplayTransfer(const GPU::Regs::DisplayTransferConfig& config) {
     MICROPROFILE_SCOPE(OpenGL_Blits);