erase regions instead of using `builtin_deref`
erase regions instead of using `builtin_deref`

The reason we were invoking `builtin_deref` was to enable comparisons
when the type was `&T`. For the reasons outlined in the comment, those
comparisons failed because the regions disagreed.

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