Activator performance improvement

Shouldn't close the previous PR early. Turns out I did not have to change much of my design.

Pinging previous trackers
@pranavkm
@halter73 
@rynowak
@ipjohnson
@yishaigalatzer 
I think we can get rid of ActivatorUtility. 

ActivatorUtility is a static class anyway, so if we kept it, we could new up a TypeActivator and it would effectively be as Singleton.