bpo-41540: AIX: skip test that is flaky with a default ulimit. (GH-21890) (#21893)

- AIX has extreme over-allocation that is in no relation to the physical
    RAM and swap.

(cherry picked from commit 39dab24621122338d01c1219bb0acc46ba9c9956)

Authored-by: Stefan Krah <skrah@bytereef.org>
1 file changed