Revert of [heap] Unify evacuating an object for new and old generation. (patchset #2 id:20001 of https://codereview.chromium.org/1481873002/ )

Reason for revert:
Still investigating bad canary.

Original issue's description:
> [heap] Unify evacuating an object for new and old generation.
>
> BUG=chromium:524425
> LOG=N
>
> Committed: https://crrev.com/afb8bcce8ba889280ed747eb218d287ddd233b4a
> Cr-Commit-Position: refs/heads/master@{#32365}

TBR=mlippautz@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:524425

Review URL: https://codereview.chromium.org/1483963004

Cr-Commit-Position: refs/heads/master@{#32460}