[Modernize] smoke-test-slow.js (#8574)
[Modernize] smoke-test-slow.js (#8574)

* [Monernize] smoke-test-slow.js

* Wrap with try finally

HeroicEric/ember-cli,balinterdi/ember-cli,jrjohnson/ember-cli,elwayman02/ember-cli,kategengler/ember-cli,thoov/ember-cli,asakusuma/ember-cli,raycohen/ember-cli,HeroicEric/ember-cli,buschtoens/ember-cli,elwayman02/ember-cli,buschtoens/ember-cli,balinterdi/ember-cli,jgwhite/ember-cli,ember-cli/ember-cli,thoov/ember-cli,kategengler/ember-cli,ember-cli/ember-cli,HeroicEric/ember-cli,ember-cli/ember-cli,thoov/ember-cli,raycohen/ember-cli,HeroicEric/ember-cli,jgwhite/ember-cli,thoov/ember-cli,jgwhite/ember-cli,jgwhite/ember-cli,asakusuma/ember-cli,jrjohnson/ember-cli