Replace `test` with `it` in TutorialAsync.md (#8921)
Replace `test` with `it` in TutorialAsync.md (#8921)

`it` is used everywhere in TutorialAsync.md except for one test where `test` is used. This commit replaces that `test` with an `it` to keep things consistent and because there does not seem to be a good reason to use `test` over `it` here.
cpojer/jest,cpojer/jest,cpojer/jest,facebook/jest,facebook/jest,facebook/jest