This way, each lazy function needs to handle only the data relevant to
itself. This reduced data handling overheads.

Other changes:

1) Don't deserialize the data; once it's on the heap, it can stay there. Lazy
function compilation is only done in the main thread.

2) Separate ProducedPreParsedScopeData and ConsumedPreParsedScopeData. It's clearer, because:

- The data looks fundamentally different when we're producing it and when we're
  consuming it.

- Cleanly separates the operations we can do in the "producing phase" and in the
  "consuming phase".

Bug: v8:5516
Change-Id: I6985a6621f71b348a55155724765624b5d5f7c33
Reviewed-on: https://chromium-review.googlesource.com/528094
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46347}