Trying to get a decent stacktrace of a release crash by disabling assertions I found a lot of unused variable warnings that break the build due to -Werror. Fix them
Pull request: https://github.com/WebKit/WebKit/pull/7476
Committed 257784@main (b9d802d8c645): <https://commits.webkit.org/257784@main> Reviewed commits have been landed. Closing PR #7476 and removing active labels.
<rdar://problem/103297948>