Change condition ordering in `parse_tt`.
Change condition ordering in `parse_tt`.

This is a small win, because `Failure` is much more common than
`Success`.

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