[account compression] Clean up tests

[ngundotra]

It is not eminently clear that zero-length instructions work, so add a test case for this in e2e tests.

Addresses concern in #5092

[ngundotra]

@jnwng @buffalojoec @joncinque Before adding some features to SPL account compression (in follow up PRs), do you guys have any preference on how the SPL Account Compression test suite is written?

[buffalojoec]

@jnwng @buffalojoec @joncinque Before adding some features to SPL account compression (in follow up PRs), do you guys have any preference on how the SPL Account Compression test suite is written?

From what I can tell all of the JS libraries do tests their own way, but we are migrating all of them to use pnpm over npm or yarn, so if you wanted to configure your package.json and test suite for that, it would be a help. Shouldn't be much of a change!

Specifically how the tests are written: I don't have any objections myself!

[buffalojoec]

@joncinque might not be the place to discuss but this did remind me of Solana Bankrun, which we can use to test our JS libs.
https://kevinheavey.github.io/solana-bankrun/

[ngundotra]

Okay, I actually split up the tests into a few different spots, should run a bit faster on local now since they can be parallelized by jest. Also way easier to read now.

Should be evident from the tests/accounts/canopy.test.ts that zero length transfer works.

[joncinque]

Do you guys have any preference on how the SPL Account Compression test suite is written?

Jest is normally the recommended test suite over mocha. And definitely use bankrun rather than spinning up a test validator to test against, if you can!