Try to stabilize reloptions test, again.
Since the test requires reproducible behavior from VACUUM, and since
DISABLE_PAGE_SKIPPING doesn't actually disable all forms of page
skipping, let's use a temporary table to avoid contention.
Back-patch to 12, like commit
3414099c.
Discussion: https://postgr.es/m/
20220120052404.sonrhq3f3qgplpzj%40alap3.anarazel.de