Update planner tool to set both partitioning param index and partitionin...

...g param value,

regardless of whether statement has been compiled to a parameterized plan.

Add the tests which caught this bug.
Ok, I've updated this method produce better diagnostics---I didn't know about the optional first argument to assertTrue.  I've definitely experienced first hand how better error messages can save a lot of time.

I've not worked a whole lot with code that actually uses exceptions.  They are kind of cool, but it's also disconcerting to me how control flow may jump out of the current block, when it's not always obvious which line might be throwing.