Yes, the slots are being initialized from the original index (the point I was trying to make is that we're setting up the page's index to point to `pg_intl_orig_index` before we've actually initialized `pg_intl_orig_index`.  I've rewritten the comment, hopefully it's better now.

Yes, we're avoiding the extra allocation by allocating the WT_PAGE_INDEX and the array of refs together, we're also avoiding an extra allocation by allocating the WT_PAGE and the original index array of WT_REFs together.