Krzysztof Gogolewski authored Mar 09, 2020 and Marge Bot committed Mar 10, 2020

- Remove Note [Existentials in shift_con_pat].
  The function shift_con_pat has been removed 15 years ago in 23f40f0e.
- Remove kcLookupTcTyCon - it's the same as tcLookupTcTyCon
- Remove ASSERT in tyConAppArgN. It's already done by getNth,
  and it's the only reason getNth exists.
- Remove unused function nextRole