* Remove the `Paged` memory initialization variant
This commit simplifies the `MemoryInitialization` enum by removing the
`Paged` variant. The `Paged` variant was originally added for uffd, but
that support has now been removed in #4040. This is no longer necessary
but is still used as an intermediate step of becoming a `Static` variant
of initialized memory (which copy-on-write uses). As a result this
commit largely modifies the static initialization of memory steps and
folds the two methods together.
* Apply suggestions from code review
Co-authored-by: Peter Huene <peter@huene.dev>
Co-authored-by: Peter Huene <peter@huene.dev>