### 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
{
		const GDScript *top = this;
		while (top) {
			{
				HashMap<StringName, Variant>::ConstIterator E = top->constants.find(p_name);
				if (E) {
					r_ret = E->value;
					return true;
				}
			}
			{
				HashMap<StringName, Ref<GDScript>>::ConstIterator E = subclasses.find(p_name);
				if (E) {
					r_ret = E->value;
					return true;
				}
			}
			top = top->_base;
		}
		if (p_name == GDScriptLanguage::get_singleton()->strings._script_source) {
			r_ret = get_source_code();
			return true;
		}
	}
	return false;
}
bool GDScript::_set(const StringName &p_name, const Variant &p_value) {