Avoid named constructors for Value and Control and the hack to also have
them on subclasses.
Instead, add a new template type and a constructor to create the subtype
from this template. Instead of the named constructors on the subtype,
we now create a template and initialize the subtype from the template.

R=herhut@chromium.org

Bug: v8:8562
Change-Id: I374fc4104ab1ae5769c587bdf5a4ca7f9a0a10d7
Reviewed-on: https://chromium-review.googlesource.com/c/1382454Reviewed-by: Stephan Herhut <herhut@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58408}