Rtl.isnan() is missing on iOS

It’s still there on 8.3.90.1927, but it’s missing on 8.3.90.1951

Thanks, logged as bugs://74623

it’s not in rtl anymore, it’s in system (global function in RemObjects.Elements.System)

bugs://74623 got closed with status nochangereq.

bugs://i62676 was closed as fixed.

Logged as bugs://i62676.