Tune the query planner to be more aggressive about using automatic indexes
on views and subqueries for which there is not opportunity to declare a
persistent schema index.
Size reduction and substantial performance increase for cellSizePtr().
Fix to payload size overflow detection in the cellSizePtr() change of
the previous check-in.
Adjust skip-scan cost estimates slightly so that a full table scan is
preferred over a skip-scan to a column with only two distinct values.