Algebraically simplify add/sub with carry/overflow

Previously, the `{add,sub}{Int,Word}C#` PrimOps weren't handled
in PrelRules (constant folding and algebraic simplification) at all.
This implements the necessary logic, so that using these primitives
isn't too punishing compared to their well-optimised, overflow-unaware
counterparts.

This is so that using these primitives in `enumFromThenTo @Int` can
be optimized by constant folding, reducing closure sizes.

Reviewers: bgamari, simonpj, hsyl20

Reviewed By: bgamari, simonpj

Subscribers: AndreasK, thomie, carter

GHC Trac Issues: #8763

Differential Revision: https://phabricator.haskell.org/D4605