Handle case where <init> callback does not capture null assignemnt

[ftc]

In the benchmark from commit f8a1fca25a9ed015fb75cc4bb2f1810088cd945d directory Historia/notebooks/reachExpGPT/FragmentLF.

When a field is declared on a class, it sometimes doesn't handle a field pointing to null initially.

e.g. For the field field a vc requiring f.field -> null cannot be satisfied for some reason. This looks like an encoding issue.

class Foo extends Fragment{
Object field; 
...
}

Workaround is to just set field to null.

class Foo extends Fragment{
Object field = null;  // explicit null set.
...
}