RFR: 8234573: ZGC: Enable ZVerifyMarking by default in debug builds

[Stefan Karlsson]

Looks good.

StefanK

On 2019-11-21 12:11, Per Liden wrote:
> Just like we have ZVerifyRoots enabled by default in debug builds, I 
> think we should also enabled ZVerifyMarking, since it's fairly inexpensive.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8234573
> Webrev: http://cr.openjdk.java.net/~pliden/8234573/webrev.0
> 
> /Per