Summary:
These checks were useful when developing Quandary, but do not fire anymore.
`AccessPath.raw_equal` is implicated as one of the top time-consuming functions in Quandary, so gating the assertion that calls it needlessly might save us some time.
Also minor cleanup: made the error messages a bit clearer and added an mli.
Reviewed By: jeremydubreil
Differential Revision: D4323653
fbshipit-source-id: 2a723b5