[8u] RFR (XS): Backport 8162540: Crash in C2 escape analysis with assert: "node should be registered"

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8162540/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8162540

It's a backport of JDK-8162540 into 8u.

The bug can lead to broken code being generated in product binaries when 
Unsafe.getAndSetObject() or Unsafe.compareAndSwapObject() are used (some 
details are described in JDK-8198543).

The fix from 9 doesn't apply cleanly, but minor adjustments are enough.

Thanks!

Testing: failing test, hotspot/test/

Best regards,
Vladimir Ivanov

[1] https://bugs.openjdk.java.net/browse/JDK-8198543