When ObjectToString is installed on Object.prototype twice (once in v8natives.js, and once in harmony-tostring.js), this pollutes old code spaces on some devices. To prevent this, the function is only installed once, preventing test failures when the --harmony-tostring flag is flipped on by default.

BUG=v8:3502
LOG=N
R=arv@chromium.org

Review URL: https://codereview.chromium.org/1072083002

Cr-Commit-Position: refs/heads/master@{#27720}