RFR: Adapt upstream object pinning API

[Aleksey Shipilev]

On 04/04/2018 07:02 PM, Zhengyu Gu wrote:
> Adapted upstream object pinning API, also made adjustment to critical native support to use new API.
> 
> 
> Webrev: http://cr.openjdk.java.net/~zgu/shenandoah/pin_interface/webrev.00/

*) The changeset contains JDK-8200429 only, make sure you are pushing the correct changeset:
 http://cr.openjdk.java.net/~zgu/shenandoah/pin_interface/webrev.00/shenandoah-jdk10.changeset

*) Since you are renaming the RT stubs, should you also rename the MacroAssembler entries? Does it
do something special for arrays, or is it just the stub for the call to
SharedRuntime::{pin|unpin}_object?

  MacroAssembler::pin_critical_native_array
  MacroAssembler::unpin_critical_native_array

Thanks,
-Aleksey