Change virtual methods in ArrayData to take Object pointer

Pass a pointer to the underlying object instead of the ArrayData
to virtual methods that modify the arrayData. This prepares
for allocating the ArrayData together with the array itself.

Change-Id: I66fe187f8b1e4d382ab243a518dbde5f18a1d16d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Allocate the ArrayData object and it's data together

Reduce the amount of allocations required for Arrays, and
allows freeing the array data more easily in the GC.

Change-Id: I3e3213f089c45c83a227038ce444aa60b2735b7f
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>