Update Ember-Inspector Compatibility

[pete-the-pete]

Adding _oldWillDestroy to the prototype

Addressing ember-inspector error when using nativeProperties.

An example of the error:

2i6k580nwyl2cogqdnfyozj0i:19088 Uncaught Error: Cannot set a non-whitelisted property _oldWillDestroy on type FOO
    at Proxy.setUnknownProperty (2i6k580nwyl2cogqdnfyozj0i:19088:63)
    at Object.set (2i6k580nwyl2cogqdnfyozj0i:19029:99)
    at e.retainObject (<anonymous>:4280:54)
    at RenderTree._serializeObject (<anonymous>:2172:19)
    at RenderTree._serializeItem (<anonymous>:2164:31)
    at <anonymous>:2145:28
    at Array.forEach (<anonymous>)
    at RenderTree._serializeDict (<anonymous>:2144:25)
    at RenderTree._serializeArgs (<anonymous>:2127:21)
    at RenderTree._serializeRenderNode (<anonymous>:2112:22)

This issue is also mentioned here: adopted-ember-addons/ember-changeset#589

I tested this manually by linking ember-m3, reinstalling, and running my app and launching ember-inspector.