normalize associated types in both self_ty and self_arg_ty
normalize associated types in both self_ty and self_arg_ty

I was only doing it for self_arg_ty, and ended up causing
run-pass/associated-types-projection-from-known-type-in-impl.rs to fail.

GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust