RFR [8u]: Bulk backport to sh/jdk8u

[Roman Kennke]

> http://cr.openjdk.java.net/~shade/shenandoah/backports/jdk8u-20171120/webrev.01/
>
> Important performance changes:
>
> rev 10197 : [backport] Passive should opt-in the barriers, not opt-out
> rev 10198 : [backport] Enable biased locking for Shenandoah by default
>
> Barrier change was amended with two guards to make tests pass.
>
> Testing: hotspot_gc_shenandoah {fastdebug|release}
>
> Thanks,
> -Aleksey
>
>
So we don't have any ways to exlude acmp, storeval, etc barriers in 8u?

Roman