We already have some logic to try to get a reasonable name for the
function when logging code. It looks up the name custom section, and
falls back to the function index. Extract this into a helper, and call
it when disassembly the code.

Bug: v8:12098
Change-Id: Ieebe6594bc3184fa655f878faa0cb67c248d7f56
Fixed: v8:12098
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3125355Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76769}