build-snapshots causes permadiffs

[leighmcculloch]

When running make build-snapshots files keep getting written that appear as permanent diffs.

Either these files need ignoring from git, or need updating, but it is unclear to me which is the path to take.

cc @chadoh

[stellarsaur]

After looking at the generated files, it doesn't look like these should be tracked. So IMO it would be best adding the outputted files to .gitignore. Open to hearing other's thoughts

[chadoh]

These files are used in the tests in cmd/crates/soroban-spec-typescript/boilerplate.rs

I think we (used to) have a CI step to make sure that these artifacts are not stale. Maybe it was ignored, and that's why we're getting perma-diffs on main now? Or maybe it was turned off?

For now, we should probably commit the diffs. After #1037 is merged, maybe we can get rid of them, since this will do much better than just making sure the built artifacts match what we expect.