Add Symbol.iterator features flags to test generation files

src/async-generators/yield-star-async-next.case

...async-generators/yield-star-getiter-async-get-abrupt.case

.../yield-star-getiter-async-not-callable-boolean-throw.case

...s/yield-star-getiter-async-not-callable-number-throw.case

...s/yield-star-getiter-async-not-callable-object-throw.case

...s/yield-star-getiter-async-not-callable-string-throw.case

...s/yield-star-getiter-async-not-callable-symbol-throw.case

...rators/yield-star-getiter-async-null-sync-get-abrupt.case

...c-generators/yield-star-getiter-async-returns-abrupt.case

...ators/yield-star-getiter-async-returns-boolean-throw.case

...nerators/yield-star-getiter-async-returns-null-throw.case

...rators/yield-star-getiter-async-returns-number-throw.case

...rators/yield-star-getiter-async-returns-string-throw.case

...rators/yield-star-getiter-async-returns-symbol-throw.case

...ors/yield-star-getiter-async-returns-undefined-throw.case

...s/yield-star-getiter-async-undefined-sync-get-abrupt.case

src/async-generators/yield-star-getiter-sync-get-abrupt.case

...s/yield-star-getiter-sync-not-callable-boolean-throw.case

...rs/yield-star-getiter-sync-not-callable-number-throw.case

...rs/yield-star-getiter-sync-not-callable-object-throw.case