Investigate Note [Kind checking recursive type and class declarations]

Note [Kind checking recursive type and class declarations] in TcTyClsDecls describes adding the tycons of a mutually recursive group both to the global env't and the local env't during kind checking.

1. Is this true?

2. If it is true, do we need to do it?

I conjecture that the answer to one of these questions is "no". If so, I will fix. This likely changed at some point with heavier reliance on TcTyCons.