[TIMOB-19338] iOS: cacheSize property does not work on XML

The ScrollableView does not load onto the screen when I assign the cacheSize property in the XML, like:

<Alloy>
    <ScrollableView id="slider" cacheSize=5 />
</Alloy>

It also does not work when I assign a string cacheSize="5". Feature seems to work when i add it using .tss:

"#slider": {
  cacheSize: 5
}