No issue: removed what seems to be useless and incorrect block of code
Issue #1491: Parenthesis in odd-numbered token is ignored before arrow function

Signed-off-by: Anton Kovalyov <anton@kovalyov.net>
No issue: Show build status for 2.x instead of master
No issue: don't filter by (error) in tests.

THIS COMMIT INTENTIONALLY BREAKS THE BUILD. We've been missing many
"Too many errors" situations in the test runner.
No issue: fix tests to respect Too Many Errors and Unrecoverable Syntax Error situations
Issue #1494: Add support for the Nashorn JavaScript engine
Issue #1494: Followup to add readFully as a global
No issue: remove message about the 'es5' option.