Updates to tests reflecting the diangostic changes in previous commit.

Updates to tests reflecting the diangostic changes in previous commit.

It is worth pointing out that the reason that so few diagnostics are
effected is because of the filter I put in where it only goes down the
new path if the borrowed place is *not* a prefix of the dropped place.

(Without that filter, a *lot* of the tests would need this change, and
it would probably be a net loss for the UX, since you'd see it even in
cases like borrows of generic types where there is no explicit mention
of `Drop`.)