In this bug, we might replace a phi node with the Dead node even though
it still has uses. DeadCodeElimination picks this up and inserts a
runtime crash into the code.

Bug: chromium:974474
Change-Id: Iea685913c8666806972719bbfb0891e516207d4f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1669693
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62352}