Refactor variable names in remove_self_joins_one_group()
Rename inner and outer to rrel and krel, respectively, to highlight their
connection to r and k indexes. For the same reason, rename imark and omark
to rmark and kmark.
Discussion: https://postgr.es/m/
18c6bd6c-6d2a-419a-b0da-
dfedef34b585%40gmail.com
Author: Andrei Lepikhov <lepihov@gmail.com>
Reviewed-by: Greg Sabino Mullane <htamfids@gmail.com>
Backpatch-through: 18