RFR: 8256507: Add a micro benchmark for JDK-8153005 [v2]

[Weijun Wang]

On Wed, 18 Nov 2020 13:50:14 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Weijun Wang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   not static anymore
>
> I think the benchmark can be simplified.

New commit. No more static fields. Thanks. @shipilev.

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PR: https://git.openjdk.java.net/jdk/pull/1277