objArrayKlass::allocate_instance() in Valhalla is a public method currently.

Since Valhalla complicates allocation of arrays, with different "flavors" (ArrayProperties), it would be best to mark it private, and only allow the oopFactory to use it.

Ad-hoc uses elsewhere will be hard to maintain as ArrayProperties evolve.

Note there may remain "friend" use from mainline allowing circumvention (i.e. Deoptimization).