### Godot version

v4.0.3.stable.official [5222a99f5]
Master [6101240231600c871f5c5473872532c68ea3268c] (confirmed by https://github.com/godotengine/godot/issues/77666#issuecomment-1568952502)

### System information

Window 10

### Issue description

References are not unreferenced at the end of `if` scopes.

### Steps to reproduce

Copy, paste and run the snippet below, check the results:

```gdscript
extends Node


func _ready() -> void:
  var ref := RefCounted.new()
  var ref_count : int

  # OK
  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # OK
  if true:
    var temp := ref
    temp = null

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # FAIL
  if true:
    var temp := ref

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)
```

Output example:

```
Expected: 1, Result: 1
Expected: 1, Result: 1
Expected: 1, Result: 2
```

### Minimal reproduction project

N/A
ERR_FAIL_COND_V_MSG(p_node->type != Node::VARIABLE, false, R"("@onready" annotation can only be applied to class variables.)");
	if (current_class && !ClassDB::is_parent_class(current_class->get_datatype().native_type, SNAME("Node"))) {
		push_error(R"("@onready" can only be used in classes that inherit "Node".)", p_annotation);
	}
	VariableNode *variable = static_cast<VariableNode *>(p_node);
	if (variable->is_static) {
		push_error(R"("@onready" annotation cannot be applied to a static variable.)", p_annotation);
		return false;
	}
	if (variable->onready) {
		push_error(R"("@onready" annotation can only be used once per variable.)", p_annotation);
		return false;
	}
	variable->onready = true;
	current_class->onready_used = true;
	return true;
}
template <PropertyHint t_hint, Variant::Type t_type>
bool GDScriptParser::export_annotations(const AnnotationNode *p_annotation, Node *p_node) {