Add test for overriding property based :host selector from outside.
Add test for overriding property based :host selector from outside.

gronke/polymer,yforrest/polymer,jordanyaker/polymer,gazal-k/polymer,ktiedt/polymer,gronke/polymer,Polymer/polymer,mgiuffrida/polymer,gronke/polymer,gazal-k/polymer,ikeagold/polymer,JeremybellEU/polymer,mgiuffrida/polymer,jordanyaker/polymer,jordanyaker/polymer,Polymer/polymer,yforrest/polymer,ikeagold/polymer,mgiuffrida/polymer,gazal-k/polymer,JeremybellEU/polymer,ktiedt/polymer,ikeagold/polymer,MartinsThiago/polymer,yforrest/polymer,JeremybellEU/polymer,MartinsThiago/polymer,Polymer/polymer,ktiedt/polymer,MartinsThiago/polymer