* Disallow escape sequences in async
* Disallow escape sequences in get, set and async in class
* invalid escape tests
* Update whitelist
* tests for async in parens
* Add test for invalid newline between params and arrow
* Move canInsertSemilcolon() into shouldPArseAsyncArrow
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
