Choice computed-bignums

The Report recommends, but does not require, that Schemes support exact integers of "practically unlimited size and precision". Some Schemes coerce large integers to inexact numbers instead, and others allow overflow. Oddly, the results can differ depending on whether the integers are input as literals or computed within the program. Compare literal-bignums.

This choice is tested for by running

(* (expt 10 8) (expt 10 8) (expt 10 8) (expt 10 8) (expt 10 8))

in each Scheme.