Use require in unit tests

[ceyonur]

We should adopt require package in our unit tests rather than using t.Fatal or assert. These are mainly in vm_test file.

In AvalancheGo we use a golangci config that forces using require, we can force it here as well.

[morrisettathena]

I can take a look

[ceyonur]

I can take a look

Much appreciated 🙌 . I assigned it to you

[darioush]

@morrisettjohn one thing to be careful here is to avoid modifying tests we take from upstream. We will want to be as textually similar to upstream in files shared with upstream.

[morrisettathena]

Sounds good! I'll try to be careful not to modify those tests then