Stabilize regression tests

During the AUTOVACUUM regression tests, unintended AUTOVACUUM runs
occasionally occurred on unrelated catalogs, notably in pg_collation,
causing test failures. Given that the information from theses tables
was not crucial for the tests, the check targets are limited to the
public schema.

(fix #138)

Author: horiguti

test/script/function-logger.sh

@@ -243,6 +243,8 @@ SELECT
 	CASE WHEN duration IS NOT NULL THEN 'xxx' END AS duration
 FROM
 	statsrepo.autovacuum
+WHERE
+	schema = 'public'
 ORDER BY
 	database, schema, "table";
 EOF