Problem:

The function row_build_index_entry_low() takes a dtuple_t object ('row') and
dict_index_t object ('index') as input and returns a new dtuple_t object
('entry') as output.  The dtuple_t object 'row' that is given as input might
have been constructed from a different dict_index_t object (!= index).  So
when accessing the externally stored data of the given 'row' we need to make
use of the correct index object.

Solution:

Store the page size information in the associated row_ext_t object.

rb#6086 approved by Vasil and Jimmy.