[8u20] RFR(XS): 8038048: assert(null_obj->escape_state() == PointsToNode::NoEscape, etc)

[Vladimir Kozlov]

8u20 backport request. These changes were pushed into jdk9 yesterday and 
nightly testing shows no problems. I will wait one more night and push 
it tomorrow if everything okay.

Changes from jdk9 applied to 8u without conflicts.

http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/054e88be4820
https://bugs.openjdk.java.net/browse/JDK-8038048

Thanks,
Vladimir