Couple of changes in TAtomic,Lockable and H2O.Cleaner and all data imports.
TAtomic changed to:
   1) preserve only backed mask from the _persist flag, but set onDisk to FALSE, as TAtomic is essentially changing the object making any disk copy obsolete.
   2) assert on underlying value being on ice or not persisted, as we do not want to be changing values which are backed by read-only data source.

Memory cleaner:
   Changed to ignore all Lockables. This is to avoid potential races with ongoing locking atomic operations.

Import form nfs, hdfs and s3 changed to to mark ValueArray headers as not persisted.