47c1921b9a
This allows us to re-use the `normalize` method on `TypeCheck`, which is important since normalization may create fresh region variables. This is not an ideal solution, though, since the current representation of "liveness constraints" (a vector of (region, point) pairs) is rather inefficient. Could do somewhat better by converting to indices, but it'd still be less good than the older code. Unclear how important this is.