Description
After reviewing LUCENE-3494, i checked other queries and noticed that BlockJoinQuery currently throws UOE for getBoost and setBoost:
throw new UnsupportedOperationException("this query cannot support boosting; please use childQuery.setBoost instead");
I don't think we can safely do that in queries, because other parts of lucene rely upon this working... for example BQs rewrite when
it has a single clause and erases itself.
So I think we should just pass down the boost to the inner weight.