Fix array handling for delete statements (#841)

[Fyren]

I think the intent with the dim.array.level check was to error if the expression wasn't the last dimension in the array, but level holds how many levels are below. So for something like int arr[2][2][2], both arr[0][0] (which is like int[2]) and arr[0][0][0] (which is like int) have a level of 0.

Removing iARRAYCHAR and iARRAYCELL just let it go on and check if the actual type can be deleted for such expressions. I don't know what kind of expression would have led to a null sym, though.