Keep stats up to date for partitioned tables

Keep stats up to date for partitioned tables

In the long-going saga for analyze on partitioned tables, one thing I
missed while reverting 0827e8af70f4 is the maintenance of analyze count
and last analyze time for partitioned tables.  This is a mostly trivial
change that enables users assess the need for invoking manual ANALYZE on
partitioned tables.

This patch, posted by Justin and modified a bit by me (Álvaro), can be
mostly traced back to Hosoya-san, though any problems introduced with
the scissors are mine.

Backpatch to 14, in line with 6f8127b73901.

Co-authored-by: Yuzuko Hosoya 
Co-authored-by: Justin Pryzby 
Co-authored-by: Álvaro Herrera 
Reported-by: Justin Pryzby 
Discussion: https://postgr.es/m/20210816222810[email protected]