### 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
GDScriptParser::DataType base_type = parser.get_tree()->base_type;
			if (base_type.kind == GDScriptParser::DataType::CLASS) {
				Ref<GDScript> bf = GDScriptCache::get_full_script(base_type.script_path, err, path);
				if (err == OK) {
					bf = Ref<GDScript>(bf->find_class(base_type.class_type->fqcn));
					if (bf.is_valid()) {
						base_cache = bf;
						bf->inheriters_cache.insert(get_instance_id());
					}
				}
			}
			members_cache.clear();
			member_default_values_cache.clear();
			_signals.clear();
			members_cache.push_back(get_class_category());
			for (int i = 0; i < c->members.size(); i++) {
				const GDScriptParser::ClassNode::Member &member = c->members[i];
				switch (member.type) {
					case GDScriptParser::ClassNode::Member::VARIABLE: {
						if (!member.variable->exported) {
							continue;
						}
						members_cache.push_back(member.variable->export_info);
						Variant default_value;
						if (member.variable->initializer && member.variable->initializer->is_constant) {
							default_value = member.variable->initializer->reduced_value;
							GDScriptCompiler::convert_to_initializer_type(default_value, member.variable);
						}
						member_default_values_cache[member.variable->identifier->name] = default_value;
					} break;