RFR 8210856: Move InstanceKlass DependencyContext cleaning to SystemDictionary::do_unloading()

[dean.long at oracle.com]

Hi Coleen.  The fix seems straightforward now, so I'm wondering, was 
there something that changed since the earlier JDK-8143408 was fixed 
that allows us to do this simpler fix now, like walking classes in 
ClassLoaderData::unload?

dl

On 9/21/18 8:45 AM, coleen.phillimore at oracle.com wrote:
> Summary: Already walk classes in ClassLoaderData::unload so generalize 
> to also clean nmethod dependencies.
>
> The nmethod dependencies should be cleaned before metadata is purged.  
> See bug for more details.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8210856.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8210856
>
> Tested with hs tier1-7, modified gtest, and 
> compiler/codecache/stress/RandomAllocationTest.java from bug 
> https://bugs.openjdk.java.net/browse/JDK-8143408.
>
> Thanks,
> Coleen
>
>