### 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
GDScriptTokenizer::Token op = previous;
	BinaryOpNode *operation = alloc_node<BinaryOpNode>();
	reset_extents(operation, p_previous_operand);
	update_extents(operation);
	Precedence precedence = (Precedence)(get_rule(op.type)->precedence + 1);
	operation->left_operand = p_previous_operand;
	operation->right_operand = parse_precedence(precedence, false);
	complete_extents(operation);
	if (operation->right_operand == nullptr) {
		push_error(vformat(R"(Expected expression after "%s" operator.")", op.get_name()));
	}
	
	switch (op.type) {
		case GDScriptTokenizer::Token::PLUS:
			operation->operation = BinaryOpNode::OP_ADDITION;
			operation->variant_op = Variant::OP_ADD;
			break;
		case GDScriptTokenizer::Token::MINUS:
			operation->operation = BinaryOpNode::OP_SUBTRACTION;
			operation->variant_op = Variant::OP_SUBTRACT;
			break;
		case GDScriptTokenizer::Token::STAR:
			operation->operation = BinaryOpNode::OP_MULTIPLICATION;
			operation->variant_op = Variant::OP_MULTIPLY;
			break;
		case GDScriptTokenizer::Token::SLASH:
			operation->operation = BinaryOpNode::OP_DIVISION;
			operation->variant_op = Variant::OP_DIVIDE;
			break;