Always load ember-testing package eagerly

[ef4]

In ember-source 5.6 (now in beta), we refactored the way Ember and its test-only pieces find each other to no longer be dependent on the AMD loader.

But this mean it's no longer sufficient to define() and not evaluate the ember-testing package in order to install the test support. It must actually get evaluted first.

Note that this bug does not manifest on embroider main, because there implicit-test-modules are eagerly evaluated. This is only a problem on stable, when using staticEmberSource: true.

[ef4]

I manually tested this against the beta. We don't currently have the ember beta in CI, and should also address that.

[patricklx]

i tried to fix it for ember < 5.6 like this now:

let amdModules: { runtime: string; buildtime: string }[] = [
      {
        runtime: 'ember-testing',
        buildtime: 'ember-testing'
      }
    ];

but thats not working since the imports are already loaded before ember-testing is set with define

[mansona]

So there is a bit of a similarity between the remaining failures on this PR and my pojo PR #1653 🤔 I don't know if that gives us a clue to what is going on here