### Godot version

4.0.beta10

### System information

Windows 11

### Issue description
UPDATE: This problem only occurs when the source code contains inner classes

Before 4.0.Beta9, I could get a GDScript instance by `GDScript.new()` and then set the `source_code` property and then `reload()`, but now it throws an error 
```
USER SCRIPT ERROR: Parse Error: Could not find script "".
   at: GDScript::reload (built-in:1644)
```
In my software, I use the above method when the user modifies the code text, and then read the godot log to implement real-time error checking of the custom user script editor. But now this functionality is completely broken

### Steps to reproduce

1. Create a GDScript instance by `GDScript.new()`
2. set the `source_code` property and then `reload()`

### Minimal reproduction project

N/A
script_frame_time = 0;
	_debug_call_stack_pos = 0;
	int dmcs = GLOBAL_DEF(PropertyInfo(Variant::INT, "debug/settings/gdscript/max_call_stack", PROPERTY_HINT_RANGE, "1024,4096,1,or_greater"), 1024);
	if (EngineDebugger::is_active()) {
		
		_debug_max_call_stack = dmcs;
		_call_stack = memnew_arr(CallLevel, _debug_max_call_stack + 1);
	} else {
		_debug_max_call_stack = 0;
		_call_stack = nullptr;
	}
#ifdef DEBUG_ENABLED
	GLOBAL_DEF("debug/gdscript/warnings/enable", true);
	GLOBAL_DEF("debug/gdscript/warnings/treat_warnings_as_errors", false);
	GLOBAL_DEF("debug/gdscript/warnings/exclude_addons", true);
	for (int i = 0; i < (int)GDScriptWarning::WARNING_MAX; i++) {
		GDScriptWarning::Code code = (GDScriptWarning::Code)i;
		Variant default_enabled = GDScriptWarning::get_default_value(code);
		String path = GDScriptWarning::get_settings_path_from_code(code);
		GLOBAL_DEF(GDScriptWarning::get_property_info(code), default_enabled);
	}
#endif 
}
GDScriptLanguage::~GDScriptLanguage() {
	singleton = nullptr;
}
void GDScriptLanguage::add_orphan_subclass(const String &p_qualified_name, const ObjectID &p_subclass) {
	orphan_subclasses[p_qualified_name] = p_subclass;
}
Ref<GDScript> GDScriptLanguage::get_orphan_subclass(const String &p_qualified_name) {