Shorten array by changing the length does not shorten the array in Espruino

Thanks - yes, that's something I've known about for a while. I was sure there was an issue on GitHub for it but I can't see it now!

Did you hit this when trying to run some existing code on Espruino?

I've just tweaked Espruino to ensure that length is at least returned as a constant, so while it's not compliant, at least code that uses it will now error.