This optimization is already done on x64 (7500e507).

Bug: v8:7844
Change-Id: Iccc3bb55aa79ef1d4423576c79d9ce6f829f2828
Reviewed-on: https://chromium-review.googlesource.com/1120343
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54162}