### 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)


reduced = Vector2i(args[0], args[1]);
								break;
							case 3:
								reduced = Vector3i(args[0], args[1], args[2]);
								break;
						}
						p_for->list->is_constant = true;
						p_for->list->reduced_value = reduced;
					}
				}
				if (p_for->list->is_constant) {
					p_for->list->set_datatype(type_from_variant(p_for->list->reduced_value, p_for->list));
				} else {
					GDScriptParser::DataType list_type;
					list_type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
					list_type.kind = GDScriptParser::DataType::BUILTIN;
					list_type.builtin_type = Variant::ARRAY;
					p_for->list->set_datatype(list_type);
				}
			}
		}
	}
	GDScriptParser::DataType variable_type;
	if (list_resolved) {
		variable_type.type_source = GDScriptParser::DataType::ANNOTATED_INFERRED;
		variable_type.kind = GDScriptParser::DataType::BUILTIN;
		variable_type.builtin_type = Variant::INT;
	} else if (p_for->list) {
		resolve_node(p_for->list, false);
		GDScriptParser::DataType list_type = p_for->list->get_datatype();