Avoiding "wrong tuple length" errors at the end of VACUUM on pg_database update (Backpatch of 947789f to v12 and v13)

Hi all,

The problem mentioned in $subject has been discussed here:

https://www.postgresql.org/message-id/DM5PR0501MB38800D9E4605BCA72DD35557CCE10@DM5PR0501MB3880.namprd05.prod.outlook.com

Ths issue has been fixed by 947789f, without a backpatch to v12 (as
per 96cdeae) as the risk seemed rather limited seen from here, back
when the problem was discussed.  Unfortunately, I have seen customer
deployments on v12 and v13 playing with pg_database entries large
enough that they would have toast entries and would be able to trigger
the problem fixed in v14 at the end of a vacuum.

Any objections about getting 947789f applied to REL_13_STABLE and
REL_12_STABLE and see this issue completely gone from all the versions
supported?

Thanks,
--
Michael