Original CL description:
> Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID
>
> Now that SharedFunctionInfos have a unique ID (and the IDs are dense),
> we can use them as an index into an array, instead of using a
> WeakFixedArray where we have to do a linear scan.
>
> Hooking up liveedit is a bit more involved, see
> https://docs.google.com/presentation/d/1FtNa3U7WsF5bPhY9uGoJG5Y9hnz5VBDabfOWpb4unWI/edit
> for an overview
>
> BUG=v8:5589
> R=verwaest@chromium.org,jgruber@chromium.org
>
> Review-Url: https://codereview.chromium.org/2547483002

BUG=v8:5589
TBR=verwaest@chromium.org,jgruber@chromium.org

Review-Url: https://codereview.chromium.org/2577063002
Cr-Commit-Position: refs/heads/master@{#41734}