Fix LazyRef closure removal.
Fix LazyRef closure removal.

The previous attempt did not actually remove the closure, since
LazyRef is a case class.

sjrd/dotty,lampepfl/dotty,lampepfl/dotty,dotty-staging/dotty,som-snytt/dotty,dotty-staging/dotty,som-snytt/dotty,dotty-staging/dotty,lampepfl/dotty,sjrd/dotty,lampepfl/dotty,sjrd/dotty,sjrd/dotty,som-snytt/dotty,som-snytt/dotty,som-snytt/dotty,sjrd/dotty,dotty-staging/dotty,lampepfl/dotty,dotty-staging/dotty