RFR [8]: 2018-10-05, Bulk backports to sh/jdk8u

[Roman Kennke]

Looks ok to me.

Thanks,
Roman

> http://cr.openjdk.java.net/~shade/shenandoah/backports/jdk8u-20181005/webrev.01/
> 
> This backports recent work to sh/jdk8u:
> 
>  [backport] Make Shenandoah to use ShenandoahOWST only
>  [backport] Missed VerifyObjectEquals in VerifyJCStressTest
>  [backport] Make sure debug builds fail predictably on safepoint timeout
>  [backport] Beef up and parallelize EvilSyncBug test
>  [backport] Enable string deduplication in all marking phases
>  [backport] Precleaning should use GC workers to do actual work
>  [backport] Fix compilation errors due to missing spaces between string literal and macro
>  [backport] Remove dead-weight ShenandoahPrinter
>  [backport] Rehash and cleanup usages of ShenandoahHeap::heap()
>  [backport] Cleanup up superfluous newlines
>  [backport] Cleanup C2 debugging leftovers
> 
> I had to do a few additional things in string dedup, because 8u code expects to pass
> ShStrDedupQueues where needed.
> 
> Testing: hotspot_tier3_gc_shenandoah {fastdebug|release}
> 
> Thanks,
> -Aleksey
>