RFR (M) 8198313: Wrap holder object for ClassLoaderData in a WeakHandle

[Kim Barrett]

> On Apr 9, 2018, at 8:39 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
>> On Apr 9, 2018, at 6:21 PM, coleen.phillimore at oracle.com wrote:
>> This is the incremental change:
>> 
>> http://cr.openjdk.java.net/~coleenp/8198313.incr.05/webrev/index.html
>> 
>> Full changes:
>> 
>> open webrev at http://cr.openjdk.java.net/~coleenp/8198313.05/webrev
>> 
>> Thanks,
>> Coleen
>>> 
>>> ------------------------------------------------------------------------------
> 
> Looks good.

I forgot to mention, in WeakHandle resolve and peek, consider asserting !is_null().