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

[Guoxiong Li]

On Wed, 6 Mar 2024 14:37:25 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Trivial removing dead code.

Looks like a leftover of [JDK-8323518](https://bugs.openjdk.org/browse/JDK-8323518). One nit.

src/hotspot/share/gc/parallel/psParallelCompact.hpp line 370:

> 368:     // debug builds to prevent the code fragments from breaking.
> 369:     HeapWord*            _data_location;
> 370: #endif  // #ifdef ASSERT

Now, we only have one field here. So the word `These` in the comment should be revised to `This`? Or the comment needs more adjustment.

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Marked as reviewed by gli (Committer).

PR Review: https://git.openjdk.org/jdk/pull/18139#pullrequestreview-1920096781
PR Review Comment: https://git.openjdk.org/jdk/pull/18139#discussion_r1514700491