### 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 (p_b.is_meta_type) {
			b_type = Variant::DICTIONARY;
		} else {
			b_type = Variant::INT;
		}
	}
	GDScriptParser::DataType result;
	bool hard_operation = p_a.is_hard_type() && p_b.is_hard_type();
	if (p_operation == Variant::OP_ADD && a_type == Variant::ARRAY && b_type == Variant::ARRAY) {
		if (p_a.has_container_element_type() && p_b.has_container_element_type() && p_a.get_container_element_type() == p_b.get_container_element_type()) {
			r_valid = true;
			result = p_a;
			result.type_source = hard_operation ? GDScriptParser::DataType::ANNOTATED_INFERRED : GDScriptParser::DataType::INFERRED;
			return result;
		}
	}
	Variant::ValidatedOperatorEvaluator op_eval = Variant::get_validated_operator_evaluator(p_operation, a_type, b_type);
	bool validated = op_eval != nullptr;
	if (validated) {
		r_valid = true;
		result.type_source = hard_operation ? GDScriptParser::DataType::ANNOTATED_INFERRED : GDScriptParser::DataType::INFERRED;
		result.kind = GDScriptParser::DataType::BUILTIN;
		result.builtin_type = Variant::get_operator_return_type(p_operation, a_type, b_type);
	} else {
		r_valid = !hard_operation;
		result.kind = GDScriptParser::DataType::VARIANT;
	}
	return result;
}
bool GDScriptAnalyzer::is_type_compatible(const GDScriptParser::DataType &p_target, const GDScriptParser::DataType &p_source, bool p_allow_implicit_conversion, const GDScriptParser::Node *p_source_node) {