RendererDummy fix buffer overflow due to mesh_get_surface

servers/rendering/dummy/storage/mesh_storage.cpp

@@ -56,3 +56,10 @@ void MeshStorage::mesh_free(RID p_rid) {
 
 	mesh_owner.free(p_rid);
 }
+
+void MeshStorage::mesh_clear(RID p_mesh) {
+	DummyMesh *m = mesh_owner.get_or_null(p_mesh);
+	ERR_FAIL_COND(!m);
+
+	m->surfaces.clear();
+}

servers/rendering/dummy/storage/mesh_storage.h

@@ -116,7 +116,7 @@ public:
 
 	virtual AABB mesh_get_aabb(RID p_mesh, RID p_skeleton = RID()) override { return AABB(); }
 	virtual void mesh_set_shadow_mesh(RID p_mesh, RID p_shadow_mesh) override {}
-	virtual void mesh_clear(RID p_mesh) override {}
+	virtual void mesh_clear(RID p_mesh) override;
 
 	/* MESH INSTANCE */