RFR: 8232116: ZGC: Remove redundant ZLock in ZNMethodTable

[Per Liden]

Looks good!

/Per

On 10/10/19 5:31 PM, erik.osterlund at oracle.com wrote:
> Hi,
> 
> The safe memory reclamation technique used in the ZNMethodTable has an 
> unnecessary ZLock. This lock is statically initialized, which creates 
> some bootstrapping issues. We should remove the lock, as in the context 
> it is used, we are always protected under the CodeCache_lock.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8232116
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8232116/webrev.00/
> 
> Thanks,
> /Erik