RFR: 8244505: G1 pause time ratio calculation does not consider Remark/Cleanup

Tue Sep 15 13:57:40 UTC 2020

The computation for long and short term pause time ratios does not include Remark/Cleanup pause times. Isolate updates
to _prev_collection_pause_end_ms from update_recent_gc_times(), then have all gc pauses (including Remark/Cleanup)
recorded by update_recent_gc_times(). Patch also includes trivial clean ups to g1Policy.* files.

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Commit messages:
 - 8244505: G1 pause time ratio calculation does not consider Remark/Cleanup

Changes: https://git.openjdk.java.net/jdk/pull/183/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=183&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8244505
  Stats: 53 lines in 4 files changed: 26 ins; 14 del; 13 mod
  Patch: https://git.openjdk.java.net/jdk/pull/183.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/183/head:pull/183

PR: https://git.openjdk.java.net/jdk/pull/183