Implement simple methods on java.lang.invoke.VarHandle.

Implements the plain instance methods in VarHandle.

Adds classes for VarHandles accessing array elements, byte arrays,
byte buffers, and fields, and allows them to be instantiated via
MethodHandles and MethodHandles.Lookup.

Bug: 65872996
Test: art/test/run-test --host 710
Change-Id: Ic028a2e896c2c64846c394ce33363a8542ffd2a7
7 files changed