Test262 - New testcase -> write back javascript and compare

Maybe we should add a new tests for all the 262 tests.

That we parse the Javascript, write it back to JS from our ast and look if the JS is the same.

Ate the moment we only check in the 262 tests if we could parse, but not if we parse correctly.

Cause of this we also did not realize, for example, that we parsed PrivateProperties to the wrong AST Type