RFR: Remove ZStatReference's dropped statistics count

[Per Liden]

Thanks for reviewing!

/Per

On 03/06/2018 11:46 AM, Erik Österlund wrote:
> Hi Per,
> 
> Looks good.
> 
> Thanks,
> /Erik
> 
> On 2018-03-05 15:31, Per Liden wrote:
>> This patch removes the "dropped" count from the reference processor 
>> and instead tracks "discovered" events, so that we have the more 
>> natural "encountered", "discovered" and "enqueued" counters. Dropped 
>> could be calculated from discovered - enqueued if needed in the future.
>>
>> http://cr.openjdk.java.net/~pliden/zgc/remove_zstat_reference_dropped/webrev.0/ 
>>
>>
>> /Per
>