We forgot to eliminate the read accesses of these two cells.

Bug: v8:7790, v8:8315
Change-Id: Id175e4d96461f88759b2d29ab1d407ba4c54e733
Reviewed-on: https://chromium-review.googlesource.com/c/1286680Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56752}