Simplify testing infra / create centralized Python script that orchestrates Turnt

[ngernest]

Kevin mentioned he doesn't like our current snapshot testing setup, specifically:

1. How we have so many different file formats (.prot, .tx, .rt)
2. How we need to create duplicate versions of the same .prot file in order to supply arguments to Turnt (e.g. the same .prot file is present in both the interpreter & monitor subdirectories)

As we add more tests / larger benchmarks, it would be nice if our testing infra was simpler (to avoid duplicate versions of the same .prot file from being out of sync with each other). Kevin suggested having a centralized Python script that orchestrates Turnt. That is, for each .prot file, the Python test orchestrator figures the right inputs for Turnt for all the different styles of tests (monitor test, interpreter test, round-trip tests) and then actually invokes the right Turnt environment somehow.

[ngernest]

Note: this is by no means urgent (its not essential for the paper we're writing), this is purely a quality-of-life improvement / nice-to-have