Introduce NativeAllocationRegistry API.

The NativeAllocationRegistry API provides a way to associate native
allocations with Java objects. The native allocations will
automatically be freed when the correspondong Java object becomes
unreachable.

Use NativeAllocationRegistry for BigInt.

Bug: 23130675
Change-Id: If89dc03f0668afdecf1086280d16d2803e07a62a
11 files changed