Harden NumberToSize against overflows.

The callers to NumberToSize are supposed to validate the number, but
this adds a last line of defense.

R=jkummerow@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/72323003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17733 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Harden NumberToSize against overflows."

This reverts commit r17733 for breaking Linux build.

TBR=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/69243005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00