RFR: 8210065: ZGC: Remove mode for treating weaks as strong

[Per Liden]

On 08/28/2018 02:39 PM, Erik Österlund wrote:
> Hi,
> 
> In ZGC, the root processor has a mode for supporting treating weaks as 
> strong. This makes no sense to use for a user as it only introduces 
> memory leaks. We have supported it anyway because it was a neat 
> debugging tool while implementing concurrent reference processing. But 
> now it seems like it is time for this option to retire, as it makes the 
> root scanning code unnecessarily complicated and bug prone.
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8210065/webrev.00/

Looks good!

/Per

> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8210065
> 
> Thanks,
> /Erik