ensure no blacklist configured in test

[remicollet]

When running build with previous version installed and configured

TEST FAILURE: ../ext/opcache/tests/zzz_basic_logging.diff --
001+ Thu Jul 31 06:45:26 2025 (266802): Debug Loading blacklist file:  '/etc/opt/remi/php85/php.d/opcache-default.blacklist'
     %s Message Cached script '%sbasic_logging%s'
     Foo Bar
     %s Debug Restart Scheduled! Reason: user

[arnaud-lb]

Thank you!