[ fix ] Make traverse and friends lazy for LazyList

[buzden]

Description

This change is like #2412, but for old long-existing functions. Since Applicative interface is inherently not lazy, the current implementation was not lazy by the effect, even if the underlying monad's effect could be short-cutting. One can see an example in the added test.

Since, LazyList is still Foldable, old behaviour is reachable by converting the LazyList to List.

It may seem that this change relies on some exploiting of the breakage of monadic laws, but it is fundamental for an eager language since monad interface is inherently lazy anyway.

Should this change go in the CHANGELOG?

• If this is a fix, user-facing change, a compiler change, or a new paper
  implementation, I have updated CHANGELOG.md (and potentially also
  CONTRIBUTORS.md).