Reland of Preparse functions in the scope that was created when parsing of the function was started (patchset #1 id:1 of https://codereview.chromium.org/2365393002/ )

Reason for revert:
Stability thief found, relanding speculative reverts.

Original issue's description:
> Revert of Preparse functions in the scope that was created when parsing of the function was started (patchset #2 id:20001 of https://codereview.chromium.org/2370713003/ )
>
> Reason for revert:
> Needed for https://codereview.chromium.org/2373443003/
>
> Original issue's description:
> > Preparse functions in the scope that was created when parsing of the function was started
> >
> > This reduces the number of scopes for lazily parsed top-level functions from 3 to 1
> >
> > BUG=v8:5209
> >
> > Committed: https://crrev.com/9618d095903c604a032b33792c068f4a6169503c
> > Cr-Commit-Position: refs/heads/master@{#39725}
>
> TBR=marja@chromium.org,verwaest@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5209
>
> Committed: https://crrev.com/0cef7100da0b609403c9026fb7307192a898a390
> Cr-Commit-Position: refs/heads/master@{#39729}

TBR=marja@chromium.org,verwaest@chromium.org,hablich@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5209

Review-Url: https://codereview.chromium.org/2377593002
Cr-Commit-Position: refs/heads/master@{#39756}