Auto merge of #1732 - RalfJung:atomic_op, r=RalfJung
Auto merge of #1732 - RalfJung:atomic_op, r=RalfJung

rename atomic_op_min_max -> atomic_op

The corresponding enum is called `AtomicOp` so IMO this also makes more sense as the name for the function.

rust-lang/miri,rust-lang/miri,rust-lang/miri,rust-lang/miri