### 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
p_script->constants.insert(name, enum_value.value);
			} break;
			case GDScriptParser::ClassNode::Member::SIGNAL: {
				const GDScriptParser::SignalNode *signal = member.signal;
				StringName name = signal->identifier->name;
				Vector<StringName> parameters_names;
				parameters_names.resize(signal->parameters.size());
				for (int j = 0; j < signal->parameters.size(); j++) {
					parameters_names.write[j] = signal->parameters[j]->identifier->name;
				}
				p_script->_signals[name] = parameters_names;
			} break;
			case GDScriptParser::ClassNode::Member::ENUM: {
				const GDScriptParser::EnumNode *enum_n = member.m_enum;
				StringName name = enum_n->identifier->name;
				p_script->constants.insert(name, enum_n->dictionary);
			} break;
			case GDScriptParser::ClassNode::Member::GROUP: {
				const GDScriptParser::AnnotationNode *annotation = member.annotation;
				StringName name = annotation->export_info.name;
				
				GDScript::MemberInfo minfo;
				minfo.index = p_script->member_indices.size();
				PropertyInfo prop_info;
				prop_info.name = name;
				prop_info.usage = annotation->export_info.usage;
				prop_info.hint_string = annotation->export_info.hint_string;
				p_script->member_info[name] = prop_info;
				p_script->member_indices[name] = minfo;
				p_script->members.insert(name);