We tried to pass the load mode even for stores.

Bug: chromium:977670
Change-Id: I2527a5ca755dba343b75f54383d17e22be0a20a5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1672940
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62333}