### 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
EnumNode *enum_node = alloc_node<EnumNode>();
	bool named = false;
	if (check(GDScriptTokenizer::Token::IDENTIFIER)) {
		advance();
		enum_node->identifier = parse_identifier();
		named = true;
	}
	push_multiline(true);
	consume(GDScriptTokenizer::Token::BRACE_OPEN, vformat(R"(Expected "{" after %s.)", named ? "enum name" : R"("enum")"));
	HashMap<StringName, int> elements;
#ifdef DEBUG_ENABLED
	List<MethodInfo> gdscript_funcs;
	GDScriptLanguage::get_singleton()->get_public_functions(&gdscript_funcs);
#endif
	do {
		if (check(GDScriptTokenizer::Token::BRACE_CLOSE)) {
			break; 
		}
		if (consume(GDScriptTokenizer::Token::IDENTIFIER, R"(Expected identifier for enum key.)")) {
			EnumNode::Value item;
			GDScriptParser::IdentifierNode *identifier = parse_identifier();
#ifdef DEBUG_ENABLED
			if (!named) { 
				for (MethodInfo &info : gdscript_funcs) {