Fix running tests with all deprecations enabled.

[kategengler]

The refactor to put the QUnit parameter directly into the EmberENV instead of using process.env to set the QUnit parameter resulted in the property being a string instead of a boolean

[kategengler]

@ef4 Can you think of a good way to guard this with a test? It is the kind of thing that can break without noticing, easily.

[ef4]

I should have hand-checked this case. Now that you've fixed it, I think it falls into the area of test infrastructure that it's more economical to trust and hand-check-when-you-touch-it than to continuously test.

But if we want to test it, I think it would require making a test that leaves detectable traces in the log output (like console.log("I checked that all deprecations are enabled"), adapting the test runner job to notice that output and make it available to subsequent jobs, and having a final job that looks at the output of all the matrix runs to assert that at least one produced the expected signature.

[kategengler]

Yeah that's the only style I could come up with too -- I agree that we just need to keep an eye on it.