Add `natToInt` coersions in the definition of `scIntegerConst` so the resulting term is a type-correct integer value.
Add `natToInt` coersions in the definition of `scIntegerConst` so the
resulting term is a type-correct integer value.

GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script