[MERGE] Add test for smart client invoking server-side hook on set_last_revision_info

[Andrew Bennetts]

John Arbash Meinel wrote:
[...]
> 
> BB:tweak
> 
> I think it is genuinely necessary to do this, but I also think it needs to be
> done at a higher level.
> 
> Namely, at WT.commit() and WT/Branch.push

Yeah.  I've been wondering about that.  Maybe this should be blackbox test?

Of course, there's lots of high-level operations like commit and push that a
smart client might use to change a remote branch tip.  E.g. there's also
uncommit, and there's all the different switches you can give e.g. push.  We
really don't want to test all possible combinations end-to-end.  We just want to
do enough that we are confident we won't break things accidentally.

If this wouldn't have been enough to catch your set_rh change, then I guess this
does need to be broader though.  Maybe one blackbox test for each of commit,
push and uncommit?

Thanks for the feedback!

-Andrew.