### 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)


HashMap<Variant, GDScriptParser::ExpressionNode *, VariantHasher, StringLikeVariantComparator> elements;
	for (int i = 0; i < p_dictionary->elements.size(); i++) {
		const GDScriptParser::DictionaryNode::Pair &element = p_dictionary->elements[i];
		if (p_dictionary->style == GDScriptParser::DictionaryNode::PYTHON_DICT) {
			reduce_expression(element.key);
		}
		reduce_expression(element.value);
		if (element.key->is_constant) {
			if (elements.has(element.key->reduced_value)) {
				push_error(vformat(R"(Key "%s" was already used in this dictionary (at line %d).)", element.key->reduced_value, elements[element.key->reduced_value]->start_line), element.key);
			} else {
				elements[element.key->reduced_value] = element.value;
			}
		}
	}
	
	GDScriptParser::DataType dict_type;
	dict_type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
	dict_type.kind = GDScriptParser::DataType::BUILTIN;
	dict_type.builtin_type = Variant::DICTIONARY;
	dict_type.is_constant = true;
	p_dictionary->set_datatype(dict_type);
}
void GDScriptAnalyzer::reduce_get_node(GDScriptParser::GetNodeNode *p_get_node) {
	GDScriptParser::DataType result;
	result.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
	result.kind = GDScriptParser::DataType::NATIVE;
	result.native_type = SNAME("Node");
	result.builtin_type = Variant::OBJECT;
	if (!ClassDB::is_parent_class(parser->current_class->base_type.native_type, result.native_type)) {