Summary:
This diff imports the new files related to setting stats on relations and attributed.
Files were copied based off of Postgres commit 24503fa95cd8cd57a8d695a910056a1cfcbacefc
These changes are not yet part of the Makefile so they are not built.
The pg_proc.dat file changes have also not been included yet.

Fixes #26239
Jira: DB-15584

Test Plan: New code is not built

Reviewers: telgersma

Reviewed By: telgersma

Subscribers: yql, ybase

Differential Revision: https://phorge.dev.yugabyte.com/D42374