This changes a '<' to a '<=' and adds a comment to explain why it is
safe to use a jump table where the maximum distance is exactly
{kMaxCodeSpaceSize}.

R=jkummerow@chromium.org

Bug: chromium:1151364
Change-Id: Id4971a2e9095fa99df48367ab09af4adbfadffaf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2552906Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71337}