Implement animationFrame() yieldable

[Turbo87]

This PR implements a animationFrame() utility that wraps the native requestAnimationFrame() API and can be used via yield animationFrame() (similar to yield timeout(1000 / 60)).

Related: #169

[maxfierke]

two tiny docs things I noticed

[maxfierke]

Cool, looks great to me. Could you add a quick test?

[Turbo87]

Could you add a quick test?

any suggestions on how to test this? 😅

[maxfierke]

Could add a unit test that stubs out rAF (sinon should be available in the test suite) and asserts that the correct things are called and that the task runs to completion without error (might not even need to stub out rAF)

Adding to these existing tests too would be good:

• tests/types/ember-concurrency-test.ts, need a test for the types
• tests/unit/cancelable-promise-helpers-test.js#L392 can add to that existing test to ensure the cancelation behavior works

[Turbo87]

@maxfierke I've added some tests but I fail to understand why the TS typing tests are failing. They seem to work alright locally.

@chancancode any clues?

[Turbo87]

@maxfierke @chancancode any ideas how to proceed? the failing tests seem unrelated to the code that I introduced here 🤔

[maxfierke]

Looks like those typescript tests are also failing in #368. I'll take a look at it this week and try and figure it out

[maxfierke]

@Turbo87 master's passing now, if you want to give this a rebase?

[Turbo87]

hmm, seems there is still an unrelated test failing. or maybe it's just flaky. can you restart the failed test to check?

[maxfierke]

yeah, that's just a flaky one. I queued up a restart on that failed job but doesn't seem to be taking. I'll merge as-is