Fuzz segments in pro tests

[PaulRBerg]

As explained here, fuzzing arrays is quite difficult in Solidity.

However, given our business logic, it would be extremely beneficial to have a suite of tests that fuzz the segments, testing different values for the amounts, milestones, and exponents.

The difficulty lies in the fact that our segments have special constraints - they can't be just any random sequence of data. Specifically, in the successful function execution paths, both of the following conditions must pass:

1. The amounts must add up to the net deposit amount.
2. The milestones must be ordered.

When I attempted to fuzz the arrays during the development of #220, I ended up giving up because I was getting too many test rejects, and also the test runs were unbearably slow (though I can't remember if that was, in part, caused by the activation of via IR).

Here's a GitHub Gist with quick sort algorithm I wrote back then, which might be handy when we pick this task up again:

https://gist.github.com/paulrberg/61e5a90434bd4bad31d9dbe9dd0c500e

[PaulRBerg]

Update: it looks like Solady's LibSort.sol might be a good fit for this.