* Ignore fixture directories that do not contain input or exec
* Fix parser test fixtures structures for some imported esprima tests.
* Warn on test folders that are not empty and do not contain testfiles
* handle disordered rest parameter in function expressions
* remove spaces [lint]
* polish function parameters validation
* add test with arrow function and comma after rest parameter [babel-parser]
The extra field parenthesizedArgument was never set to true. It was
always set to false and the code that read this was incorrectly
checking if extra was present.
Fixes#7957
