### 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
virtual void set_datatype(const DataType &p_datatype) { datatype = p_datatype; }
		virtual bool is_expression() const { return false; }
		virtual ~Node() {}
	};
	struct ExpressionNode : public Node {
		
		bool reduced = false;
		bool is_constant = false;
		Variant reduced_value;
		virtual bool is_expression() const override { return true; }
		virtual ~ExpressionNode() {}
	protected:
		ExpressionNode() {}
	};
	struct AnnotationNode : public Node {
		StringName name;
		Vector<ExpressionNode *> arguments;
		Vector<Variant> resolved_arguments;
		AnnotationInfo *info = nullptr;
		PropertyInfo export_info;
		bool is_resolved = false;
		bool is_applied = false;
		bool apply(GDScriptParser *p_this, Node *p_target);
		bool applies_to(uint32_t p_target_kinds) const;
		AnnotationNode() {