Improve TidyPgm.hasCafRefs to account for Integer literals (Trac #8525)
See Note [Disgusting computation of CafRefs] in TidyPgm. Also affects CoreUtils.rhsIsStatic. The real solution here is to compute CAF and arity information from the STG-program, and feed it back to tidied program for the interface file and later GHCi clients. A battle for another day. But at least this commit reduces the number of gratuitous CAFs, and hence SRT entries. And kills off a batch of ASSERT failures.