RFR: 8330847: G1 accesses uninitialized memory when predicting eden copy time

[Thomas Schatzl]

Hi all,

  please review this change that fixes survivor rate predictor initialization when expanding the survivor rate prediction tables.

Before JDK-8231579 these predictors were not used when finalizing the collection set at gc start, and were always updated properly at the end of the GC. With that change G1 started using these uninitialized predictors.

There is an assert that should fail in the future if there is a bug.

Testing: tier1-3

Thanks,
  Thomas

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Commit messages:
 - 8330847

Changes: https://git.openjdk.org/jdk/pull/19364/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19364&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8330847
  Stats: 34 lines in 2 files changed: 20 ins; 13 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19364.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19364/head:pull/19364

PR: https://git.openjdk.org/jdk/pull/19364