Instead of these two instructions I generalize the kX64Peek instruction.

R=bmeurer@chromium.org

Change-Id: Ie5f8c7d428b65df3ca8b75594f6a06a75cc8e978
Reviewed-on: https://chromium-review.googlesource.com/839863
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50294}