fix #qt_methods on anonymous classes

Anonymous classes have a name that's nil, and #qt_methods
will bail out on them (because of find_pclassid). This breaks
core Ruby methods as e.g. instance_methods, to reproduce:

    Class.new.instance_methods
this does not work for me, i used instead:

```
3157                         if !klass.name
3158                             return meths
3159                         end

```