RFR(S) 8222425: Shenandoah: Move commonly used closures to separate files

[Aleksey Shipilev]

On 4/13/19 1:16 AM, Zhengyu Gu wrote:
> Please review this patch that refactors some shared closures to separate files.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8222425
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8222425/webrev.00/

Looks okay. Have you tested this without PCH? Are they actually used somewhere outside of
ShenandoahHeap, e.g. in shConcurrentMark/shTraversalGC?

-Aleksey