RFR: Cherry-pick fix: 8193133: Assertion failure because 0xDEADDEAD can be in-heap

[Roman Kennke]

Applies to aarch64-port/jdk8u only:

Bug:
https://bugs.openjdk.java.net/browse/JDK-8193133

Webrev:
http://cr.openjdk.java.net/~rkennke/aarch64-jdk8u-movoops/webrev.01/

Pushed in:
http://hg.openjdk.java.net/aarch64-port/jdk8u/hotspot/rev/97df73117bbe

I want to cherry-pick it into shenandoah/jdk8u. Ok?

Roman