[8u] RFR 8231779: crash HeapWord*ParallelScavengeHeap::failed_mem_allocate

[Zhengyu Gu]

I would like to backport this patch to 8u for parity with Oracle 8u271.

The original patch does not apply cleanly. But the conflicts are minors:

1) Copyright line does not match.
2) Last block is under Universe::heap() != NULL check in 8u, while 
original version does not have such check.

Original bug: https://bugs.openjdk.java.net/browse/JDK-8231779
Original patch: https://hg.openjdk.java.net/jdk/jdk/rev/fcbd54a2c2d9


8u Webrev: http://cr.openjdk.java.net/~zgu/JDK-8231779-8u/webrev.00/

Test:
   tier1 on Linux 86_64

Thanks,

-Zhengyu