Move logging, updating and testing utils into common directory

This is part of a series of PRs which add up to a substantive change.

I used '.' in import statements in some places to bring the symbols into the current namespace, to reduce the quantity of diffs in this patch.  I can do it the other way if preferred.
I am not sold on having this in common. Certainly not in its current form. I suggest we remove it from this PR, so it doesn't hold up merging.