### 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 err;
		}
	}
#ifdef DEBUG_ENABLED
	
	if (p_keep_state) {
		for (RBSet<Object *>::Element *E = p_script->instances.front(); E;) {
			RBSet<Object *>::Element *N = E->next();
			ScriptInstance *si = E->get()->get_script_instance();
			if (si->is_placeholder()) {
#ifdef TOOLS_ENABLED
				PlaceHolderScriptInstance *psi = static_cast<PlaceHolderScriptInstance *>(si);
				if (p_script->is_tool()) {
					
					p_script->placeholders.erase(psi); 
					GDScriptInstance *instance = memnew(GDScriptInstance);
					instance->base_ref_counted = Object::cast_to<RefCounted>(E->get());
					instance->members.resize(p_script->member_indices.size());
					instance->script = Ref<GDScript>(p_script);
					instance->owner = E->get();
					
					for (const KeyValue<StringName, GDScript::MemberInfo> &F : p_script->member_indices) {
						instance->member_indices_cache[F.key] = F.value.index;
					}
					instance->owner->set_script_instance(instance);
					
					Callable::CallError ce;
					p_script->initializer->call(instance, nullptr, 0, ce);
					if (ce.error != Callable::CallError::CALL_OK) {