The inferred name in the function literal might not be as accurate as the one
already on the shared function info, so use the existing one instead.

BUG=chromium:995813

Change-Id: Ie06eb964934fc039e56ebf9452f706e1192b7ab0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1782169
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63566}