### 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 (err) {
				push_error(vformat(R"(Could not resolve script "%s": %s.)", script_path, error_names[err]), p_source);
				return;
			}
			ERR_FAIL_COND_MSG(!parser_ref->get_parser()->has_class(p_class), R"(Parser bug: Mismatched external parser.)");
			GDScriptAnalyzer *other_analyzer = parser_ref->get_analyzer();
			GDScriptParser *other_parser = parser_ref->get_parser();
			int error_count = other_parser->errors.size();
			other_analyzer->resolve_class_interface(p_class);
			if (other_parser->errors.size() > error_count) {
				push_error(vformat(R"(Could not resolve class "%s".)", p_class->fqcn), p_source);
			}
			return;
		}
		p_class->resolved_interface = true;
		if (resolve_class_inheritance(p_class) != OK) {
			return;
		}
		GDScriptParser::DataType base_type = p_class->base_type;
		if (base_type.kind == GDScriptParser::DataType::CLASS) {
			GDScriptParser::ClassNode *base_class = base_type.class_type;
			resolve_class_interface(base_class, p_class);
		}
		for (int i = 0; i < p_class->members.size(); i++) {
			resolve_class_member(p_class, i);
#ifdef DEBUG_ENABLED
			if (!has_static_data) {
				GDScriptParser::ClassNode::Member member = p_class->members[i];
				if (member.type == GDScriptParser::ClassNode::Member::CLASS) {
					has_static_data = member.m_class->has_static_data;