Move nio direct byte buffers onto the Java heap.

Specifically, implement VMRuntime.newNonMovableArray and VMRuntime.addressOf.
For now these are pretty trivial because we don't have a copying collector,
but this (a) prevents code from allocating arbitrary amounts of direct byte
buffer without being charged for it, and (b) lets us move to a copying
collector in future.

Change-Id: I5de156dc8ac4ab5c997e18d447f635eb01ff08ab
1 file changed