RFR: Adjust metaspace size during each GC

[Aleksey Shipilev]

On 10/27/2018 01:54 PM, Zhengyu Gu wrote:
> Of course, also for full GC:
> Updated: http://cr.openjdk.java.net/~zgu/shenandoah/adj_metaspace/webrev.01/index.html

OK. We have to do this during safepoint, right? Otherwise it seems sensible to put this call near
Universe::update_heap_info_at_gc() call in shControlThread.

-Aleksey