### 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
parse_class_name();
				}
				break;
			case GDScriptTokenizer::Token::EXTENDS:
				advance();
				if (head->extends_used) {
					push_error(R"("extends" can only be used once.)");
				} else {
					parse_extends();
					end_statement("superclass");
				}
				break;
			case GDScriptTokenizer::Token::LITERAL:
				if (current.literal.get_type() == Variant::STRING) {
					
					advance();
					if (!match(GDScriptTokenizer::Token::NEWLINE)) {
						push_error("Expected newline after comment string.");
					}
					break;
				}
				[[fallthrough]];
			default:
				
				can_have_class_or_extends = false;
				break;
		}
		if (panic_mode) {
			synchronize();
		}