This method was used to implement deserialization via the value
serializer. It was deprecated since this functionality is not used any
more, and hence untested.
This CL cleans up by removing the deprecated method and two private
helper methods.

R=adamk@chromium.org

Bug: v8:10155
Change-Id: I4dda1949fd4f1b499cb6f8d6e6a76b642179303a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2033171Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66096}