Re: Refactoring the regression tests for more independence

Hi hackers,

> > I don't see anything shocking after a quick glance, and I don't think any
> > review is going to give any more confidence compared to the script-dep-testing
> > script, so +1 for pushing them since the cf bot is green again.
>
> Done, will watch the farm.

I wanted to test one of the patches we have for the July CF on the
Raspberry Pi 3 Model B+. It runs Raspbian GNU/Linux 10 (buster) and
Linux Kernel 5.10.60-v7+.

I discovered that the PostgreSQL tests don't pass in this environment.
Using `git bisect` I was able to pinpoint the problem to cc50080a and
found this thread. Currently `REL_15_STABLE` and `master` are
affected.

To build PostgreSQL I use my regular set of scripts [1] and the
following command:

```
./quick-build.sh && ./single-install.sh && make installcheck
``

regression.diffs and regression.out are attached. The same tests pass
just fine on Ubuntu Linux and MacOS.

I didn't investigate the problem further since it's pretty late in my
timezone. I just wanted to share my current discoveries with you.
Since we have several agents on buildfarm running Raspbian that are
pretty happy with the patch I would guess this may have something to
do with particular flags and/or configure options I'm using.

[1]: https://github.com/afiskon/pgscripts/

--
Best regards,
Aleksander Alekseev