Fixing async tests and other NIT changes

src/class-elements/private-field-as-arrow-function.case

...class-elements/private-field-as-async-arrow-function.case

src/class-elements/private-field-as-async-function.case

src/class-elements/private-field-as-function.case

src/class-elements/private-field-super-access-throws.case

...s/class/elements/private-field-as-async-arrow-function.js

...essions/class/elements/private-field-as-async-function.js

...sions/class/elements/private-field-super-access-throws.js

...s/class/elements/private-field-as-async-arrow-function.js

...tements/class/elements/private-field-as-async-function.js

...ments/class/elements/private-field-super-access-throws.js