Move the "if (!((start >= 128) && (character < 128))) {" check
 outside while (start <= end) loop.

Bug: v8:9731
Change-Id: I1f7e2fea189f0eba0b52100ac8d4063e7d79a306
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1832911Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64194}