### 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
int gcc = CoreConstants::get_global_constant_count();
	for (int i = 0; i < gcc; i++) {
		_add_global(StaticCString::create(CoreConstants::get_global_constant_name(i)), CoreConstants::get_global_constant_value(i));
	}
	_add_global(StaticCString::create("PI"), Math_PI);
	_add_global(StaticCString::create("TAU"), Math_TAU);
	_add_global(StaticCString::create("INF"), INFINITY);
	_add_global(StaticCString::create("NAN"), NAN);
	
	List<StringName> class_list;
	ClassDB::get_class_list(&class_list);
	for (const StringName &n : class_list) {
		if (globals.has(n)) {
			continue;
		}
		Ref<GDScriptNativeClass> nc = memnew(GDScriptNativeClass(n));
		_add_global(n, nc);
	}
	
	List<Engine::Singleton> singletons;
	Engine::get_singleton()->get_singletons(&singletons);
	for (const Engine::Singleton &E : singletons) {
		_add_global(E.name, E.ptr);
	}
#ifdef TESTS_ENABLED
	GDScriptTests::GDScriptTestRunner::handle_cmdline();
#endif
}
String GDScriptLanguage::get_type() const {