ISPN-4670 Move PredicateIndex.PredicateSubscriptions to Predicates.Subscription
ISPN-4670 Remove unused retur type of BENode.handleChildValue
ISPN-4670 Only repeated predicates really need to be unsusbscribed after are satisfied
ISPN-4670 Refactor Predicate/Predicates to not use IntervalTrees for the single-filter usage scenario

* Usage of IntervalTrees is beneficial only when we have many predicates, like in the continuous query use case but it slows things down in the single-filter scenario