RFR: Build: Update to JDK 15.0.2 [v2]

[Andrea Cosentino]

On Thu, 4 Feb 2021 14:36:34 GMT, Erik Helin <ehelin at openjdk.org> wrote:

>> Andrea Cosentino has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains one additional commit since the last revision:
>> 
>>   Build: Update to JDK 15.0.2
>
> Looks good! ��

Thanks for reviewing, we now need a second reviewer right?

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PR: https://git.openjdk.java.net/skara/pull/989