RFR: Rework GC degradation on allocation failure

[Roman Kennke]

Am 17.05.2018 um 20:31 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/alloc-failure-rework/webrev.01/
> 
> I was doing the ClassUnloading fixes and realized that one of my stress tests did not fail as
> expected with OOMe. Instead, Shenandoah tried futively to do the GC cycles over and over again,
> never stopping. The fixes for that path are in this patch. It required some work in defining what
> the GC progress is. New tests verify Shenandoah fails as expected.
> 
> Testing: hotspot_gc_shenandoah
> 
> Thanks,
> -Aleksey
> 

But, but... that was a feature, not a bug!! Shenandoah never runs out of
memory! ;-)

Otherwise, what Zhengyu noted.

Thanks!
Roman