RFR(s): ZGC: C2: Dont clone in self loop

[Aleksey Shipilev]

On 05/29/2018 01:11 PM, Nils Eliasson wrote:
> http://cr.openjdk.java.net/~neliasso/zgc/fix_clone_self/webrev/

This seems to fix the stack overflow I was seeing.

-Aleksey