Revert of [heap] Remove live weak cells from weak cell list when finalizing incremental marking. (patchset #3 id:40001 of https://codereview.chromium.org/1474303002/ )

Reason for revert:
Still investigating bad canary.

Original issue's description:
> [heap] Remove live weak cells from weak cell list when finalizing incremental marking.
>
> BUG=chromium:548562
> LOG=n
>
> Committed: https://crrev.com/6190c608c8f3ced0f00ff53965e115b78646cecd
> Cr-Commit-Position: refs/heads/master@{#32372}

TBR=ulan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:548562

Review URL: https://codereview.chromium.org/1481383004

Cr-Commit-Position: refs/heads/master@{#32459}