RFR: 8350758: G1: Use actual last prediction in accumulated survivor rate prediction too

[Thomas Schatzl]

Hi all,

  please review this fix to recent JDK-8349906 to use the current
survivor rate in the accumulated survivor rate for initializing newly allocated entries as well.

Testing: gha

Thanks,
  Thomas

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Commit messages:
 - 8350758

Changes: https://git.openjdk.org/jdk/pull/23795/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23795&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350758
  Stats: 16 lines in 1 file changed: 5 ins; 8 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/23795.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23795/head:pull/23795

PR: https://git.openjdk.org/jdk/pull/23795