ExecutionContext.evaluateHandle accepts arguments that are either
serializable, or JSHandles. A potential confusion is that it *does not*
accept arguments that *contain* JSHandles.
This patch adds a log message warning when it encounters that situation.
Fixes#3562
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.
