ConstraintAnalysis: Increment constants (#8969)

If we know `x == C` and have `x++`, we can set it to `x == C + 1`, etc.

A risk when computing this is that we might end up doing `x++` from
0 to 1 to 2 to 3 and so forth, until we reach some high limit. Add a
mechanism to assert on such pointless work.

This is necessary to compute loop overflows.