Setting the highest bit first saves cost for repeatedly growing the
underlying bitvector.

R=jkummerow@chromium.org

Bug: v8:13063
Change-Id: Ic324caa20c91dd6f55760944c3dafe7f1dc018b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3776340
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81849}