Chrome DevTools shows anonymous scripts with yellow background and names
them with `debugger://VM<scriptId>` prefix.
This patch starts reporting the same debugger:// urls for anonymous
scripts in puppeteer's JS coverage. This might simplify debugging, e.g.
using `debugger;` statement to reveal the script in DevTools and later
matching it against the one in the coverage.
This patch adds `reportAnonymousScripts` option to the `coverage.startJSCoverage` method. With this option, anonymous scripts are reported as well.
Fixes#2777
Today, we have tests split into multiple files, with files pulling
tests from some other files.
This patch starts explicitly gathering all tests from the same
`test.js` file.
Drive-By: move one test from `browser.spec.js` into `puppeteer.spec.js`
since it starts browser itself.
