Reported state size of `Constant` symbol is the size of its data, but it should be zero

[wbernoudy]

... at least I think so. Since the Constant node shares the memory backing its data across states, I believe the estimated state size (as reported by Constant.state_size()) should be zero.

[arcondello]

That state_size() is primarily used as part of the submission to Leap. In that context we do make a copy of the Constant's data and store it as a NumPy array in the serialized file. We then load that file later. I think with caching that duplication might be undone after loading.... but it gets complicated.