[Analyzer] Extend ConstraintAssignor to handle remainder op

Summary:
`a % b != 0` implies that `a != 0` for any `a` and `b`. This patch
extends the ConstraintAssignor to do just that. In fact, we could do
something similar with division and in case of multiplications we could
have some other inferences, but I'd like to keep these for future
patches.

Fixes https://bugs.llvm.org/show_bug.cgi?id=51940

Reviewers: noq, vsavchenko, steakhal, szelethus, asdenyspetrov

Subscribers:

Differential Revision: https://reviews.llvm.org/D110357