Revert "[turbofan] add value input to DeadValue" and "[turbofan] add regression test for chromium:796041"

This reverts
https://chromium-review.googlesource.com/c/v8/v8/+/848995
and
https://chromium-review.googlesource.com/c/v8/v8/+/847011

Bug: chromium:798938
Change-Id: I4be8e5bca77037a278fd9882f0d76de1ae12c23f
TBR: jarin@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/849995Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50356}