Although, doesn't do anything with them yet. The idea is to simplify
  the use of trace to make it a lot more useful than it currently is.

  This is not fully satisfactory as it pollutes a bit the prelude. Ideally, those functions should only be visible
  and usable by the underlying trace code. But for now, we'll just go with it.

  Somehow, we have to patch some function in gen_uplc because of the
  module name. I have to look further into this because it isn't normal.

  This is a little weird but, prelude functions are handled slightly
  differently.

  Actually, this has been a bug for a long time it seems. Calling any
  prelude functions using a qualified import would result in a codegen
  crash. Whoopsie.

  This is now fixed as shown by the regression test.

  - Trace-if-false are now completely discarded in compact mode.

  - Only the label (i.e. first trace argument) is preserved.

  - When compiling with tracing _compact_, the first label MUST unify to
    a string. This shouldn't be an issue generally speaking and would
    enforce that traces follow the pattern

    ```
    label: arg_0[, arg_1, ..., arg_n]
    ```

  Note that what isn't obvious with these changes is that we now support
  what the "emit" keyword was trying to achieve; as we compile now with
  user-defined traces only, and in compact mode to only keep event
  labels in the final contract; while allowing larger payloads with
  verbose tracing.

  We've never been using those 'expected' tokens captured during
  parsing, which is lame because they contain useful information!

  This is much better than merely showing our infamous

    "Try removing it!"