test[S8Struct] ref and deref

"should work to ref and then deref 1 level deep"
| type s ss |
type := S8Struct type: #(#(d double)).
s := S8Struct type: type values: #d -> Number pi.
ss := s ref deref.
ss @ #d = Number pi ifFalse: [ self error: 'Wrong contents' ].