### 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
type = ANNOTATION;
		}
	};
	struct ArrayNode : public ExpressionNode {
		Vector<ExpressionNode *> elements;
		ArrayNode() {
			type = ARRAY;
		}
	};
	struct AssertNode : public Node {
		ExpressionNode *condition = nullptr;
		ExpressionNode *message = nullptr;
		AssertNode() {
			type = ASSERT;
		}
	};
	struct AssignableNode : public Node {
		IdentifierNode *identifier = nullptr;
		ExpressionNode *initializer = nullptr;
		TypeNode *datatype_specifier = nullptr;
		bool infer_datatype = false;
		bool use_conversion_assign = false;
		int usages = 0;
		virtual ~AssignableNode() {}
	protected:
		AssignableNode() {}
	};
	struct AssignmentNode : public ExpressionNode {
		
		enum Operation {