### 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
calls = 0;
	ERR_FAIL_COND(singleton);
	singleton = this;
	strings._init = StaticCString::create("_init");
	strings._notification = StaticCString::create("_notification");
	strings._set = StaticCString::create("_set");
	strings._get = StaticCString::create("_get");
	strings._get_property_list = StaticCString::create("_get_property_list");
	strings._property_can_revert = StaticCString::create("_property_can_revert");
	strings._property_get_revert = StaticCString::create("_property_get_revert");
	strings._script_source = StaticCString::create("script/source");
	_debug_parse_err_line = -1;
	_debug_parse_err_file = "";
	profiling = false;