Add async-functions feature to more files (#1830)

...xpressions/class/async-meth-dflt-params-trailing-comma.js

...ssions/class/async-meth-params-trailing-comma-multiple.js

...ressions/class/async-meth-params-trailing-comma-single.js

...expressions/class/async-meth-static-dflt-params-abrupt.js

...ss/async-meth-static-dflt-params-arg-val-not-undefined.js

.../class/async-meth-static-dflt-params-arg-val-undefined.js

...ressions/class/async-meth-static-dflt-params-ref-later.js

...ressions/class/async-meth-static-dflt-params-ref-prior.js

...pressions/class/async-meth-static-dflt-params-ref-self.js

...ons/class/async-meth-static-dflt-params-trailing-comma.js

...class/async-meth-static-params-trailing-comma-multiple.js

...s/class/async-meth-static-params-trailing-comma-single.js

...object/method-definition/async-meth-dflt-params-abrupt.js

...efinition/async-meth-dflt-params-arg-val-not-undefined.js

...od-definition/async-meth-dflt-params-arg-val-undefined.js

...ect/method-definition/async-meth-dflt-params-ref-later.js

...ect/method-definition/async-meth-dflt-params-ref-prior.js

...ject/method-definition/async-meth-dflt-params-ref-self.js

...ethod-definition/async-meth-dflt-params-trailing-comma.js

...d-definition/async-meth-params-trailing-comma-multiple.js