[11u] RFR 8208601: Introduce native oop barriers in C2 for OopHandle

[Jaroslav Bachorík]

Hi,

Original bug:
  https://bugs.openjdk.java.net/browse/JDK-8208601
  https://hg.openjdk.java.net/jdk/jdk12/rev/0c7040d1d1ca

Backport requires JDK-8208582
<https://bugs.openjdk.java.net/browse/JDK-8208582>.
The patch does not apply cleanly due to minor differences in the context of
barrierSetC2.cpp
<http://cr.openjdk.java.net/~jbachorik/8208601/barrierSetC2.cpp.rej> but
manual resolution is extremely simple.

Rej file: http://cr.openjdk.java.net/~jbachorik/8208601/barrierSetC2.cpp.rej

11u webrev:
  http://cr.openjdk.java.net/~jbachorik/8208601/

Testing:
 - tier1
 - tier2

Thanks,

-JB-