### 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
if (previous.literal.get_type() != Variant::STRING) {
			push_error(vformat(R"(Only strings or identifiers can be used after "extends", found "%s" instead.)", Variant::get_type_name(previous.literal.get_type())));
		}
		current_class->extends_path = previous.literal;
		if (!match(GDScriptTokenizer::Token::PERIOD)) {
			return;
		}
	}
	make_completion_context(COMPLETION_INHERIT_TYPE, current_class, chain_index++);
	if (!consume(GDScriptTokenizer::Token::IDENTIFIER, R"(Expected superclass name after "extends".)")) {
		return;
	}
	current_class->extends.push_back(parse_identifier());
	while (match(GDScriptTokenizer::Token::PERIOD)) {
		make_completion_context(COMPLETION_INHERIT_TYPE, current_class, chain_index++);
		if (!consume(GDScriptTokenizer::Token::IDENTIFIER, R"(Expected superclass name after ".".)")) {
			return;
		}
		current_class->extends.push_back(parse_identifier());
	}
}
template <class T>
void GDScriptParser::parse_class_member(T *(GDScriptParser::*p_parse_function)(bool), AnnotationInfo::TargetKind p_target, const String &p_member_kind, bool p_is_static) {
	advance();
#ifdef TOOLS_ENABLED
	int doc_comment_line = previous.start_line - 1;
#endif 
	
	List<AnnotationNode *> annotations;
	while (!annotation_stack.is_empty()) {