chore(developer): add test for compiler messages and cleanup e2e test

The purpose of these tests is to ensure that our slightly WET constant
definitions for compiler errors are consistent in their usage:

  * that names are consistent between the message functions and
    constants
  * that constants have unique codes
  * that constants have the right error mask for their type

This means we don't have to worry about DRYing out the constants, which
would probably require us to have a preprocessing step, which has its
own negatives.

Also, added more reporting to e2e test in case of failures.