Stabilize output of new regression test.

Stabilize output of new regression test.

Per buildfarm, the output order of \dx+ isn't consistent across
locales.  Apply NO_LOCALE to force C locale.  There might be a
more localized way, but I'm not seeing it offhand, and anyway
there is nothing in this test module that particularly cares
about locales.

Security: CVE-2022-2625