Remove unsupported case "AtomicOps" from AIX test list.

Summary: The test-suite case `AtomicOps.c` is unsupported on 32-bit AIX. It fails at link stage and complains about undefined symbol `__sync_fetch_and_add_8` and `__sync_fetch_and_sub_8`. Compilers on the platform are consistent in not supporting these built-ins. An implementation of them would need to use locks.

Reviewers: hubert.reinterpretcast, daltenty

Reviewed By: hubert.reinterpretcast, daltenty

Subscribers: mgorny, jfb

Differential Revision:
2 files changed