performance: expression calculations are hydrated 3 times

[pinetops]

Hydrating expressions is relatively expensive: .5ms is typical in a real app for a first_name <> last_name (although using flame on, so it's probably slowed down by the instrumentation)

There may be opportunities to improve performance of the hydration, but it appears that there are circumstances where the hydration occurs 3 times in a load so if it can be done once, that would improve performance:

Top level:

Zoom in on first two examples:

Zoom in on third example: