This patch adds a new utility - `utils/bisect.js` - that accepts
a range of Chromium revisions and a pptr script and bisects the
range to figure when the script breaks.
The Puppeteer Script, given to the tool, should be exiting
with non-zero code to signify malfunctioning.
Example:
```
$ node utils/bisect.js --good 577361 --bad 599821 a.js
```
