RFR 8232712: Shenandoah: SIGBUS in load_reference_barrier_native

[Zhengyu Gu]

I missed aarch64 changes for JDK-8232010[1].

On aarch64, native barrier does not setup the second parameter 
(load_addr) for runtime call, therefore, the address to CAS is bogus.

Bug: https://bugs.openjdk.java.net/browse/JDK-8232712
Webrev: http://cr.openjdk.java.net/~zgu/JDK-8232712/webrev.00/

Test:
   hotspot_gc_shenandoah (fastdebug and release) on aarch64 Linux.

[1] https://bugs.openjdk.java.net/browse/JDK-8232010

Thanks,

-Zhengyu