Remove old/legacy test.
Remove old/legacy test.

This test predates the changes to migrate to
`additional-dev-dependencies.json`, which removes most of the original
logic that we were trying to test here.

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