RFR: 8367626: Parallel: Remove ParallelCompactData::summarize_dense_prefix

Mon Sep 15 08:28:56 UTC 2025

Remove the unnecessary summary operation on dense-prefix, because the summary operation is only needed for compaction, but dense-prefix doesn't participate in compaction.

Test: tier1-5

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Commit messages:
 - pgc-remove-dense-prefix-summary

Changes: https://git.openjdk.org/jdk/pull/27286/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27286&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367626
  Stats: 36 lines in 2 files changed: 1 ins; 31 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/27286.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27286/head:pull/27286

PR: https://git.openjdk.org/jdk/pull/27286