commonSuperclassWith: does not work with metaclasses

[Ducasse]

While

Array commonSuperclassWith: Interval
>> SequenceableCollection 

The same expression on metaclass fails.

Array class commonSuperclassWith: Interval class
```

```
commonSuperclassWith: aClass
	"return the next common superclass between me and aClass. If I am the superclass of aClass, that is me"
	<reflection: 'Class structural inspection - Iterating and querying hierarchy'>
	^ self withAllSuperclasses detect: [ :class | (aClass allSuperclasses includes: class) ] ifNone: nil
```