Update coverage test suite
Update coverage test suite

* Create a job to run the full test suite against node 10
* Isolate the coverage test suite in its own stage
* Run coverage test suite only when merging on master

HeroicEric/ember-cli,fpauser/ember-cli,HeroicEric/ember-cli,Turbo87/ember-cli,cibernox/ember-cli,fpauser/ember-cli,Turbo87/ember-cli,HeroicEric/ember-cli,jrjohnson/ember-cli,thoov/ember-cli,jgwhite/ember-cli,mike-north/ember-cli,buschtoens/ember-cli,cibernox/ember-cli,mike-north/ember-cli,ember-cli/ember-cli,jrjohnson/ember-cli,raycohen/ember-cli,thoov/ember-cli,cibernox/ember-cli,asakusuma/ember-cli,asakusuma/ember-cli,raycohen/ember-cli,jgwhite/ember-cli,jgwhite/ember-cli,fpauser/ember-cli,thoov/ember-cli,kategengler/ember-cli,buschtoens/ember-cli,balinterdi/ember-cli,HeroicEric/ember-cli,elwayman02/ember-cli,fpauser/ember-cli,mike-north/ember-cli,thoov/ember-cli,jgwhite/ember-cli,Turbo87/ember-cli,balinterdi/ember-cli,ember-cli/ember-cli,kategengler/ember-cli,mike-north/ember-cli,Turbo87/ember-cli,ember-cli/ember-cli,elwayman02/ember-cli,cibernox/ember-cli