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

src/test/regress/expected/reloptions.out

@@ -89,7 +89,7 @@ ALTER TABLE reloptions_test RESET (fillfactor=12);
 ERROR:  RESET must not include values for parameters
 -- Test vacuum_truncate option
 DROP TABLE reloptions_test;
-CREATE TABLE reloptions_test(i INT NOT NULL, j text)
+CREATE TEMP TABLE reloptions_test(i INT NOT NULL, j text)
 	WITH (vacuum_truncate=false,
 	toast.vacuum_truncate=false,
 	autovacuum_enabled=false);

src/test/regress/sql/reloptions.sql

@@ -55,7 +55,7 @@ ALTER TABLE reloptions_test RESET (fillfactor=12);
 -- Test vacuum_truncate option
 DROP TABLE reloptions_test;
 
-CREATE TABLE reloptions_test(i INT NOT NULL, j text)
+CREATE TEMP TABLE reloptions_test(i INT NOT NULL, j text)
 	WITH (vacuum_truncate=false,
 	toast.vacuum_truncate=false,
 	autovacuum_enabled=false);