Re: longfin and tamandua aren't too happy but I'm not sure why

... also, lapwing's not too happy [1].  The alter_table test
expects this to yield zero rows, but it doesn't:

 SELECT m.* FROM filenode_mapping m LEFT JOIN pg_class c ON c.oid = m.oid
 WHERE c.oid IS NOT NULL OR m.mapped_oid IS NOT NULL;

I've reproduced that symptom in a 32-bit FreeBSD VM building with clang,
so I suspect that it'll occur on any 32-bit build.  mamba is a couple
hours away from offering a confirmatory data point, though.

(BTW, is that test case sane at all?  I'm bemused by the symmetrical
NOT NULL tests on a fundamentally not-symmetrical left join; what
are those supposed to accomplish?  Also, the fact that it doesn't
deign to show any fields from "c" is sure making it hard to tell
what's wrong.)

            regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=lapwing&dt=2022-09-27%2018%3A40%3A18