RFR: 8213623: ZGC: Let heap iteration walk all roots

[Erik Österlund]

Hi Per,

Looks good.

Thanks,
/Erik

On 2018-11-09 15:49, Per Liden wrote:
> Let the ZHeapIterator walk all roots, including weak roots that might 
> be logically cleared from the application's point of view. This allows 
> e.g. for a more thorough heap verification.
>
> Also the heap iterator should access oops with AS_NO_KEEPALIVE to 
> avoid resurrecting object that would otherwise be garbage collected.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8213623
> Webrev: http://cr.openjdk.java.net/~pliden/8213623/webrev.0
>
> Testing: tier1-4
>
> /Per