### 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
signature += p_script->get_script_path();
		}
		
		signature += "::0";
		
		if (p_class->identifier) {
			signature += "::" + String(p_class->identifier->name) + "." + String(func_name);
		} else {
			signature += "::" + String(func_name);
		}
		codegen.generator->set_signature(signature);
	}
#endif
	codegen.generator->set_initial_line(p_class->start_line);
	GDScriptFunction *gd_function = codegen.generator->write_end();
	memdelete(codegen.generator);
	return gd_function;
}
Error GDScriptCompiler::_parse_setter_getter(GDScript *p_script, const GDScriptParser::ClassNode *p_class, const GDScriptParser::VariableNode *p_variable, bool p_is_setter) {
	Error err = OK;
	GDScriptParser::FunctionNode *function;
	if (p_is_setter) {
		function = p_variable->setter;
	} else {
		function = p_variable->getter;
	}
	_parse_function(err, p_script, p_class, function);
	return err;
}
Error GDScriptCompiler::_populate_class_members(GDScript *p_script, const GDScriptParser::ClassNode *p_class, bool p_keep_state) {