[Analyzer][NFC] Add RangedConstraintManager to ConstraintAssignor

In this patch we store a reference to `RangedConstraintManager` in the
`ConstraintAssignor`. This way it is possible to call back and reuse some
functions of it. This patch is exclusively needed for its child patches,
it is not intended to be a standalone patch.

Differential Revision: https://reviews.llvm.org/D111640