Potential compiler introduced timing leak

[zugzwang]

I haven't confirmed but it looks like this library is also vulnerable to https://groups.google.com/a/list.nist.gov/g/pqc-forum/c/hqbtIGFKIpU

See https://github.com/Argyle-Software/kyber/blob/476e22c1a1ed579f3030e1ae46077036dc384d7f/src/reference/poly.rs#L291

and the fix in the reference implementation https://github.com/pq-crystals/kyber/commit/9b8d30698a3e7449aeb34e62339d4176f11e3c6c