Make beforeEach & afterEach respect returned promises

[ef4]

Returning a promise from beforeEach or afterEach does not cause the tests to wait. This is inconsistent with test, which does wait. The practical workaround today is to do:

beforeEach(assert) {
  let done = assert.async();
  somethingAsynchronous().then(done);
}

But we should make promises work too.

Related issues:

• https://github.com/rwjblue/ember-qunit/issues/186
• https://github.com/rwjblue/ember-qunit/issues/165

[Turbo87]

I'm pretty sure this works by now, so I'm going to go ahead and close this issue. Please reopen if this is still a problem.