Add features tags for Atomics and SharedArrayBuffer (#1494)

test/built-ins/SharedArrayBuffer/prototype/slice/species.js

...redArrayBuffer/prototype/slice/start-default-if-absent.js

...ArrayBuffer/prototype/slice/start-default-if-undefined.js

...ns/SharedArrayBuffer/prototype/slice/start-exceeds-end.js

...SharedArrayBuffer/prototype/slice/start-exceeds-length.js

.../SharedArrayBuffer/prototype/slice/this-is-arraybuffer.js

...edArrayBuffer/prototype/slice/tointeger-conversion-end.js

...ArrayBuffer/prototype/slice/tointeger-conversion-start.js

...ins/SharedArrayBuffer/return-abrupt-from-length-symbol.js

.../built-ins/SharedArrayBuffer/return-abrupt-from-length.js

test/built-ins/SharedArrayBuffer/toindex-length.js

...built-ins/SharedArrayBuffer/undefined-newtarget-throws.js

test/built-ins/SharedArrayBuffer/zero-length.js