RFR: 8287558: Remove remset coarsening stats during g1 remset summary printing

[tqxia]

Remset summary printing prints coarsening statistics in addition to remset summaries; that information is either duplicated with "Coarsening (recent)" printouts (with gc+remset=debug) at GC start or all-zeros at GC end.

Given that Remset summary printing is enabled with gc+remset=trace which covers the recent/all coarsening statistics, the coarsening statistics during remset summary are somewhat duplicate (or useless for the after-gc one).

Remove the coarsening statistics from the remset summaries.

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Commit messages:
 - 8287558: Remove remset coarsening stats during g1 remset summary printing

Changes: https://git.openjdk.java.net/jdk/pull/8971/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8971&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8287558
  Stats: 10 lines in 2 files changed: 0 ins; 10 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8971.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8971/head:pull/8971

PR: https://git.openjdk.java.net/jdk/pull/8971