RFR: 8295156: G1: Improve constant other time calculation

[Thomas Schatzl]

Hi all,

  can I have reviews for this change from Ivan that improves current constant other time calculation, allowing for better predictions?

After many years of changes to the garbage collection algorithm, moving around phases, the current calculation of constant other time became just wrong. This change fixes this.

Depends on PR#10652, please review that one first if not done yet.

Testing: Testing: gha, local testing, tier1-5 with other changes in this patch series, perf testing with other changes in this patch series

Thanks,
  Thomas

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Depends on: https://git.openjdk.org/jdk/pull/10652

Commit messages:
 - Initial version by walulyai

Changes: https://git.openjdk.org/jdk/pull/10654/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10654&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295156
  Stats: 5 lines in 2 files changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10654.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10654/head:pull/10654

PR: https://git.openjdk.org/jdk/pull/10654