* Depends on PR #1909
* Closes#1750
* Adds recursion unrolling tests on JuvixCore
* Adds a version of the mid-square hash example without the recursion
manually unrolled
For now, the recursion is always unrolled to a fixed depth (140). In the
future, we want to add a global option to override this depth, as well
as a mechanism to specify it on a per-function basis. In a more distant
future, we might want to try deriving the unrolling depth heuristically
for each function.