### 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
ExpressionNode *parse_lambda(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_type_test(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_yield(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_invalid_token(ExpressionNode *p_previous_operand, bool p_can_assign);
	TypeNode *parse_type(bool p_allow_void = false);
#ifdef TOOLS_ENABLED
	
	int class_doc_line = 0x7FFFFFFF;
	bool has_comment(int p_line, bool p_must_be_doc = false);
	String get_doc_comment(int p_line, bool p_single_line = false);
	void get_class_doc_comment(int p_line, String &p_brief, String &p_desc, Vector<Pair<String, String>> &p_tutorials, bool p_inner_class);
#endif 
public:
	Error parse(const String &p_source_code, const String &p_script_path, bool p_for_completion);
	ClassNode *get_tree() const { return head; }
	bool is_tool() const { return _is_tool; }
	ClassNode *find_class(const String &p_qualified_name) const;
	bool has_class(const GDScriptParser::ClassNode *p_class) const;
	static Variant::Type get_builtin_type(const StringName &p_type);
	CompletionContext get_completion_context() const { return completion_context; }
	CompletionCall get_completion_call() const { return completion_call; }
	void get_annotation_list(List<MethodInfo> *r_annotations) const;
	bool annotation_exists(const String &p_annotation_name) const;
	const List<ParserError> &get_errors() const { return errors; }
	const List<String> get_dependencies() const {
		
		return List<String>();
	}
#ifdef DEBUG_ENABLED
	const List<GDScriptWarning> &get_warnings() const { return warnings; }