### 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
void print_get_node(GetNodeNode *p_get_node);
		void print_if(IfNode *p_if, bool p_is_elif = false);
		void print_identifier(IdentifierNode *p_identifier);
		void print_lambda(LambdaNode *p_lambda);
		void print_literal(LiteralNode *p_literal);
		void print_match(MatchNode *p_match);
		void print_match_branch(MatchBranchNode *p_match_branch);
		void print_match_pattern(PatternNode *p_match_pattern);
		void print_parameter(ParameterNode *p_parameter);
		void print_preload(PreloadNode *p_preload);
		void print_return(ReturnNode *p_return);
		void print_self(SelfNode *p_self);
		void print_signal(SignalNode *p_signal);
		void print_statement(Node *p_statement);
		void print_subscript(SubscriptNode *p_subscript);
		void print_suite(SuiteNode *p_suite);
		void print_ternary_op(TernaryOpNode *p_ternary_op);
		void print_type(TypeNode *p_type);
		void print_type_test(TypeTestNode *p_type_test);
		void print_unary_op(UnaryOpNode *p_unary_op);
		void print_variable(VariableNode *p_variable);
		void print_while(WhileNode *p_while);
	public:
		void print_tree(const GDScriptParser &p_parser);
	};
#endif 
	static void cleanup();
};
#endif