Add more constant operation?

While implementing NTRU, I noticed I needed a [constant time sorting algorithm](https://github.com/RustCrypto/KEMs/pull/35/commits/87c7c02a3ecd9b6afee9a51836bcca0a99c2c5ea#diff-ccdf7edb0ee2c9ed7a0ea36681a9ef13dbbab3605a8e396f59203a1e6e01fca7) and [constant time division](ntru/src/const_time/num.rs). Would it make sense to move the implementation to subtle instead to make them accessible to other implementers?