The @glimmer/destroyables package (which is re-exported here as @ember/destroyable) provides a handy utility that we can use to ensure that all objects that were setup with the destruction system have actually had destroy called on them. Read up over in emberjs/rfcs#580 for details on the enableDestroyableTracking and assertDestroyablesDestroyed methods (or destroyables in general).

This PR adds the basic ability to begin enforcing that our own test suite properly calls destroy on everything that has a destructor setup on it, this is a basic precursor to exposing the same utility to application test harnesses. At the moment, applications cannot leverage the assertDestroyablesDestroyed functionality themselves, due to framework objects themselves. This PR allows us to begin fixing that...

References

• Framework objects look to be included in undestroyed objects when using setupLifelineValidation ember-lifeline/ember-lifeline#897
• Framework objects look to be included in undestroyed objects when calling assertDestroyablesDestroyed ember-polyfills/ember-destroyable-polyfill#159