### Godot version

4.1.beta3

### System information

Fedora Workstation 38 - Godot 4.1.beta3 - Vulkan (Forward+)

### Issue description

**This is an issue created by the production team, we're working on it**

Currently, it's impossible to call virtual functions within GDScript.

This currently returns an error:
```gdscript
# a.gd
extends Node

func _process(delta: float) -> void:
	pass
```

```gdscript
# main.gd
extends Node

var my_node: Node = preload("res://a.gd").new()

func _process(delta: float) -> void:
	my_node._process(delta)  # Cannot call virtual function "_process()" because it hasn't been defined.
```

### Steps to reproduce

1. Create a script (`a.gd`) based on `Node` that declares `_process()`;
2. Create a main node;
3. Attach a script to the main node;
4. Initialize a variable with a new `a.gd` instance;
5. Try to run `_process()` on that node;
6. Find out that it returns an error.

### Minimal reproduction project

[virtual_functions.zip (updated)](https://github.com/godotengine/godot/files/11823992/virtual_functions.zip)


}
		if (ClassDB::get_signal(native, name, &method_info)) {
			
			p_identifier->set_datatype(make_signal_type(method_info));
			p_identifier->source = GDScriptParser::IdentifierNode::INHERITED_VARIABLE;
			return;
		}
		if (ClassDB::has_enum(native, name)) {
			p_identifier->set_datatype(make_native_enum_type(name, native));
			p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
			return;
		}
		bool valid = false;
		int64_t int_constant = ClassDB::get_integer_constant(native, name, &valid);
		if (valid) {
			p_identifier->is_constant = true;
			p_identifier->reduced_value = int_constant;
			p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
			
			StringName enum_name = ClassDB::get_integer_constant_enum(native, name);
			if (enum_name != StringName()) {
				p_identifier->set_datatype(make_native_enum_type(enum_name, native, false));
			} else {
				p_identifier->set_datatype(type_from_variant(int_constant, p_identifier));
			}
		}
	}
}
void GDScriptAnalyzer::reduce_identifier(GDScriptParser::IdentifierNode *p_identifier, bool can_be_builtin) {