Sync ToIntegerIfIntegral with Temporal

[ToIntegerIfIntegral](https://tc39.es/proposal-intl-duration-format/#sec-tointegerwithoutrounding) should be sync'ed with Temporal's [ToIntegerIfIntegral](https://tc39.es/proposal-temporal/#sec-tointegerifintegral), i.e. remove current step 2 so that `NaN` values throw a RangeError instead of being coerced to 0.