Merge test helpers

[marcelomorgado]

@pcowgill commented:

I agree that now is a good moment for that. OpenZeppelin has a special repo for their test helpers, so maybe we could even make them their own child package to follow their example but with more of a monorepo style.

If we do want to keep them in an existing package, we can use this question to frame it: Do the test helpers end up being used more in unit tests or integration tests? Or a little of both?

If unit, maybe action. If integration, maybe tasit SDK. If mixture, probably a new child package.

And I agree that some helpers functions could be utils functions exposed from the SDK. And it would be great if put comments near them about that like you mentioned.

Refs: #207 (comment)

[pcowgill]

This was closed by #496