Revert of Fix --max_old_space_size=4096 integer overflow. (patchset #1 id:1 of https://codereview.chromium.org/890563003/)

Reason for revert:
Win64 compile failure.

Original issue's description:
> Fix --max_old_space_size=4096 integer overflow.
>
> R=yangguo@chromium.org
>
> Committed: https://crrev.com/6253aa8908c55535473ddbe1db8e5a6f5e559b73
> Cr-Commit-Position: refs/heads/master@{#26371}

TBR=svenpanne@chromium.org,ben@strongloop.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/875053005

Cr-Commit-Position: refs/heads/master@{#26372}