Improve evaluation of objects

Too much of evaluating objects is spent within truffle boundaries, and the object model is not partial-evaluation friendly.
This is bad for performance, and likely a big reason for slow eval times.

The issue provides no file, test, or entry point to begin from. Start by locating the object-evaluation and Truffle-boundary implementation, then profile evaluation to identify the costly paths and assess what partial-evaluation-friendly object model changes would be required. Done means evaluation spends less time across Truffle boundaries and eval performance improves.

Written by the indexing model from the issue text.