The width table in CryptolTC.z3 wasn't large enough to solve constraints
about the width of 64-bit words. This change is a bit of a band-aid, as
larger words will expose the same problem. Longer-term, we should try to
solve these constraints after the SMT-based phase, using some other
approach.
The constraints in CryptoBox were too permissive, and when adjusted to
represent the true intent (that values fit within 64-bits), and the
width table was updated, the example will type-check again.
Thanks to @tommd for tracking both of these down.
