[BUG] pg_upgrade test fails from older versions.

Hello!

Found that pg_upgrade test has broken for upgrades from older versions.
This happened for two reasons.
1) In 7b378237a the format of "aclitem" changed so upgrade from <=15
fails with error:
"Your installation contains the "aclitem" data type in user tables.
The internal format of "aclitem" changed in PostgreSQL version 16
so this cluster cannot currently be upgraded... "

Tried to fix it by changing the column type in the upgrade_adapt.sql.
Please see the patch attached.

2) In 60684dd83 and b5d63824 there are two changes in the set of specific privileges.
The thing is that in the privileges.sql test there is REVOKE DELETE command
which becomes pair of REVOKE ALL and GRANT all specific privileges except DELETE
in the result dump. Therefore, any change in the set of specific privileges will lead to
a non-zero dumps diff.
To avoid this, i propose to replace any specific GRANT and REVOKE in the result dumps with ALL.
This also made in the patch attached.

Would be glad to any remarks.

With best regards,

-- 
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company