[DUX-3135] Golden tests

[9999years]

The ghciwatch log output is nondeterministically ordered because it all runs asynchronously, which precludes writing golden tests. (Also, output varies somewhat by compiler, by host operating system, etc.)

We could potentially rewrite the order log events show up in (we spawn a limited number of tasks and we know their names ahead of time) and rewrite message contents to account for compiler and platform differences.

This is Harder.

_{From SyncLinear.com | DUX-3135}