X86: Add the other variants of VarHandle.compareAndSet

This commit implements VarHandle WeakCompareAndSet,
WeakCompareAndSetPlain, WeakCompareAndSetAcquire,
WeakCompareAndSetRelease.

Test: art/test.py --host -r -t 712-varhandle-invocation --32
Change-Id: I1e0f5e7dcb21cd0f107d5a74cb534cef992ef9fc
2 files changed