Reject access to unlogged tables in contrib modules

Hi

A few contrib modules fail to handle unlogged relations during recovery,
which leads to rather unhelpful error messages:

== primary ==

create extension pgrowlocks;
create extension pgstattuple;
create extension pg_visibility;
create extension pageinspect;
create unlogged table ut as select 1;

== standby ==

psql (20devel)
Type "help" for help.

postgres=# select * from pgrowlocks('ut');
ERROR: could not open file "base/5/16458": No such file or directory
postgres=# select * from pgstattuple('ut');
ERROR: could not open file "base/5/16458": No such file or directory
postgres=# select * from pg_visibility('ut');
ERROR: could not open file "base/5/16458": No such file or directory
postgres=# select get_raw_page('ut',0);
ERROR: could not open file "base/5/16458": No such file or directory

Attached 4 patches adding checks to report a proper error message -- one
per module for easier reviewing:

psql (20devel)
Type "help" for help.

postgres=# select * from pgrowlocks('ut');
ERROR: cannot access temporary or unlogged relations during recovery
postgres=# select * from pgstattuple('ut');
ERROR: cannot access temporary or unlogged relations during recovery
postgres=# select * from pg_visibility('ut');
ERROR: cannot access temporary or unlogged relations during recovery
postgres=# select get_raw_page('ut',0);
ERROR: cannot access temporary or unlogged relations during recovery
postgres=#

I was unable to find any TAP test I could use to add these cases, and I
believe it could be an overkill to create one just to test these error
messages, so I decided to not include any tests for now. Let me know if
I am missing something here.

These bugs were reported by Zsolt (in CC) in another related thread[1]

Thanks!

Best, Jim

1 -
https://www.postgresql.org/message-id/CAN4CZFMCuiya7d5sRQ-xm%3DhKnADiT_jrppSTo%2Ba_WxktuPk2LQ%40mail.gmail.com