Changed stxstattarget in pg_statistic_ext to use nullable
representation, removing explicit -1 for default statistics target in
PostgreSQL 17.
Relevant PG commit:
012460ee93c304fbc7220e5b55d9d0577fc766ab
012460ee93
```diff
SELECT stxstattarget, stxrelid::regclass
FROM pg_statistic_ext
WHERE stxnamespace IN (
SELECT oid
FROM pg_namespace
WHERE nspname IN ('statistics''TestTarget')
)
AND stxname SIMILAR TO '%\_\d+'
ORDER BY stxstattarget, stxrelid::regclass ASC;
stxstattarget | stxrelid
---------------+-----------------------------------
- -1 | "statistics'TestTarget".t1_980000
- -1 | "statistics'TestTarget".t1_980002
...
+ | "statistics'TestTarget".t1_980000
+ | "statistics'TestTarget".t1_980002
...
```
* Remove if conditions with PG_VERSION_NUM < 13
* Remove server_above_twelve(&eleven) checks from tests
* Fix tests
* Remove pg12 and pg11 alternative test output files
* Remove pg12 specific normalization rules
* Some more if conditions in the code
* Change RemoteCollationIdExpression and some pg12/pg13 comments
* Remove some more normalization rules