### Godot version

4.0-rc6

### System information

Fedora 37, Mesa Intel ADL GT2

### Issue description

Code that works as expected at runtime fails with Nil references to (assigned) exported vars in the editor:

![tool_global_position_error](https://user-images.githubusercontent.com/364501/222031460-ffb1ecbd-5175-4a42-8470-25285ba5f821.png)


### Steps to reproduce

Try to access the `global_position` of a `Node3D` that's assigned to an exported var.

See that it works at runtime.

See that it errors in the editor with:

> Invalid get index 'global_position' (on base: 'Nil').

### Minimal reproduction project

[tool_test.zip](https://github.com/godotengine/godot/files/10856640/tool_test.zip)

return nodes.size();
}
StringName SceneState::get_node_type(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, nodes.size(), StringName());
	if (nodes[p_idx].type == TYPE_INSTANTIATED) {
		return StringName();
	}
	return names[nodes[p_idx].type];
}
StringName SceneState::get_node_name(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, nodes.size(), StringName());
	return names[nodes[p_idx].name];
}
int SceneState::get_node_index(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, nodes.size(), -1);
	return nodes[p_idx].index;
}
bool SceneState::is_node_instance_placeholder(int p_idx) const {
	ERR_FAIL_INDEX_V(p_idx, nodes.size(), false);
	return nodes[p_idx].instance >= 0 && (nodes[p_idx].instance & FLAG_INSTANCE_IS_PLACEHOLDER);
}
Ref<PackedScene> SceneState::get_node_instance(int p_idx) const {