[Bug 39411] Provide a way to monitor VM revert times

https://bugs.winehq.org/show_bug.cgi?id=39411

--- Comment #1 from Hans Leidekker  ---
(In reply to François Gouget from comment #0)
> But then one could argue that revert times should just be low and stay that
> way and that then monitoring them may not be needed.

I agree, and I believe reverts can be made fast. Currently reverting a VM means
going back to a really old image and then applying a snapshot including large
deltas, like service packs.

If we'd merge the snapshot into a new base image then the delta would be small,
it would essentially be the VM saved state and applying it should be fast.