### 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)


GDScriptParser::DataType true_type;
	if (p_ternary_op->true_expr) {
		true_type = p_ternary_op->true_expr->get_datatype();
	} else {
		true_type.kind = GDScriptParser::DataType::VARIANT;
	}
	GDScriptParser::DataType false_type;
	if (p_ternary_op->false_expr) {
		false_type = p_ternary_op->false_expr->get_datatype();
	} else {
		false_type.kind = GDScriptParser::DataType::VARIANT;
	}
	if (true_type.is_variant() || false_type.is_variant()) {
		result.kind = GDScriptParser::DataType::VARIANT;
	} else {
		result = true_type;
		if (!is_type_compatible(true_type, false_type)) {
			result = false_type;
			if (!is_type_compatible(false_type, true_type)) {
				result.kind = GDScriptParser::DataType::VARIANT;
#ifdef DEBUG_ENABLED
				parser->push_warning(p_ternary_op, GDScriptWarning::INCOMPATIBLE_TERNARY);
#endif
			}
		}
	}
	result.type_source = true_type.is_hard_type() && false_type.is_hard_type() ? GDScriptParser::DataType::ANNOTATED_INFERRED : GDScriptParser::DataType::INFERRED;
	p_ternary_op->set_datatype(result);
}
void GDScriptAnalyzer::reduce_type_test(GDScriptParser::TypeTestNode *p_type_test) {