### 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
AnnotationNode *annotation = alloc_node<AnnotationNode>();
	annotation->name = previous.literal;
	make_completion_context(COMPLETION_ANNOTATION, annotation);
	bool valid = true;
	if (!valid_annotations.has(annotation->name)) {
		push_error(vformat(R"(Unrecognized annotation: "%s".)", annotation->name));
		valid = false;
	}
	annotation->info = &valid_annotations[annotation->name];
	if (!annotation->applies_to(p_valid_targets)) {
		if (annotation->applies_to(AnnotationInfo::SCRIPT)) {
			push_error(vformat(R"(Annotation "%s" must be at the top of the script, before "extends" and "class_name".)", annotation->name));
		} else {
			push_error(vformat(R"(Annotation "%s" is not allowed in this level.)", annotation->name));
		}
		valid = false;
	}
	if (check(GDScriptTokenizer::Token::PARENTHESIS_OPEN)) {
		push_multiline(true);
		advance();
		
		push_completion_call(annotation);
		make_completion_context(COMPLETION_ANNOTATION_ARGUMENTS, annotation, 0, true);
		int argument_index = 0;
		do {
			if (check(GDScriptTokenizer::Token::PARENTHESIS_CLOSE)) {
				
				break;
			}
			make_completion_context(COMPLETION_ANNOTATION_ARGUMENTS, annotation, argument_index, true);