fix: updated test code

[tgrecojs]

@kumavis i'm not sure what the end goal is for the grain package but i thought this fix might be appreciated.

below is a screenshot of my console from a moment ago. i'm running the test with the -w flag so the passing tests show as soon as the update is saved.

note - you're likely aware of the text below but adding it in for context

this is something i frequently run into when testing hardened js code. ava needs prepare-test-env-ava.js to be the first import. just a guess here but its likely that vscode's prettier extension which automatically rearranges imports so that relative imports follow any dependency import.