### 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
head = alloc_node<ClassNode>();
	head->fqcn = script_path;
	current_class = head;
	bool can_have_class_or_extends = true;
	while (!check(GDScriptTokenizer::Token::TK_EOF)) {
		if (match(GDScriptTokenizer::Token::ANNOTATION)) {
			AnnotationNode *annotation = parse_annotation(AnnotationInfo::SCRIPT | AnnotationInfo::STANDALONE | AnnotationInfo::CLASS_LEVEL);
			if (annotation != nullptr) {
				if (annotation->applies_to(AnnotationInfo::SCRIPT)) {
					
					if (annotation->name == SNAME("@icon")) {
						annotation->apply(this, head);