### 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
if (r_error) {
		*r_error = ERR_FILE_CANT_OPEN;
	}
	Error err;
	Ref<GDScript> scr = GDScriptCache::get_full_script(p_path, err, "", p_cache_mode == CACHE_MODE_IGNORE);
	
	if (scr.is_null()) {
		
		scr.instantiate();
	}
	if (r_error) {
		*r_error = OK;
	}
	return scr;
}
void ResourceFormatLoaderGDScript::get_recognized_extensions(List<String> *p_extensions) const {
	p_extensions->push_back("gd");
	
	
	
}
bool ResourceFormatLoaderGDScript::handles_type(const String &p_type) const {