RFR: 8327477: Parallel: Remove unused ParallelCompactData::_highest_ref

[Guoxiong Li]

On Thu, 7 Mar 2024 09:22:33 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> it records the corresponding heap-addr of a region, if I read the code correctly.

I searched the code and think you are right. It is good to remove `_data_location`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18139#discussion_r1516066880