The shorter xorl + movb instructions cause regressions.

Bug: chromium:1220093
Change-Id: Ib7da0ea16669fa490b78a8095f6f3b35e972e1cb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2964396Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75161}