### 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
return static_cast<LiteralNode *>(parse_literal(nullptr, false));
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_literal(ExpressionNode *p_previous_operand, bool p_can_assign) {
	if (previous.type != GDScriptTokenizer::Token::LITERAL) {
		push_error("Parser bug: parsing literal node without literal token.");
		ERR_FAIL_V_MSG(nullptr, "Parser bug: parsing literal node without literal token.");
	}
	LiteralNode *literal = alloc_node<LiteralNode>();
	complete_extents(literal);
	literal->value = previous.literal;
	return literal;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_self(ExpressionNode *p_previous_operand, bool p_can_assign) {
	if (current_function && current_function->is_static) {
		push_error(R"(Cannot use "self" inside a static function.)");
	}
	SelfNode *self = alloc_node<SelfNode>();
	complete_extents(self);
	self->current_class = current_class;
	return self;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_builtin_constant(ExpressionNode *p_previous_operand, bool p_can_assign) {