RFR: Cherry-pick/synchronize JDK-8180175 and JDK-8180599"

[Aleksey Shipilev]

On 05/22/2017 11:22 AM, Roman Kennke wrote:
> I've upstreamed the fast synchronizer root scanning code (i.e. scan only
> thread-local monitor lists). It turned out to introduce a bug where we
> could miss monitors on thread termination, and also moved code in
> different places. This change synchronizes the corresponding code with
> what I upstreamed.
> 
> http://cr.openjdk.java.net/~rkennke/fastsync/webrev.00/
> <http://cr.openjdk.java.net/%7Erkennke/fastsync/webrev.00/>
> 
> Testing: hotspot_gc_shenandoah
> 
> Ok?

OK.

8u also needs a syncup?

-Aleksey