The IsValidSectionCode function shouldn't include internally-used
numeric identifiers of well-known optional sections.

Fixed: v8:12867
Change-Id: I9d894ee57157455e92a17ddcde94f32f05fb038d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3644612
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80494}