Add an async version ExampleMemLog
Add an async version ExampleMemLog

Right now it looks like either [corr3] or [corr3_from_corr2] are not
quite going to work. Even proving a trivial [corr3] relation on a nop
fails (see ExampleMemLog), because you end up having to prove
[crash_xform p =p=> p] for the frame predicate.

mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl