Fix assumption that only top level code won't have outer scope infos.

Bug: v8:7690
Change-Id: Ia6eec7b406632ad301e7db557597204c7ca66730
Reviewed-on: https://chromium-review.googlesource.com/1107622Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53869}