RFR: 8260586: Shenandoah: simplify "Concurrent Weak References" logging [v2]

[Aleksey Shipilev]

> Concurrent Weak References always does parallel worker operation. Therefore "Process" counter is redundant, and we might as well make the root counter the per-worker one. This simplifies GC logging.
> 
> Old log:
> 
> [95.220s][info][gc,stats] Concurrent Weak References         1709 us
> [95.220s][info][gc,stats]   Process                          1588 us, parallelism: 1.30x
> [95.220s][info][gc,stats]     CWRF: <total>                  2056 us
> [95.220s][info][gc,stats]     CWRF: Weak References          2056 us, workers (us): 454, 1450,   2, 145,   4,   1,   0,   0, 
> 
> New log:
> 
> [39.583s][info][gc,stats] Concurrent Weak References          651 us, parallelism: 1.52x
> [39.583s][info][gc,stats]   CWRF: <total>                     986 us
> [39.583s][info][gc,stats]   CWRF: Weak References             986 us, workers (us): 183,  29, 145, 627,   1,   0,   0,   0,

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into JDK-8260586-sh-log-cwr
 - 8260586: Shenandoah: simplify "Concurrent Weak References" logging

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2288/files
  - new: https://git.openjdk.java.net/jdk/pull/2288/files/8b9bf2e1..a493df7c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2288&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2288&range=00-01

  Stats: 426 lines in 28 files changed: 232 ins; 64 del; 130 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2288.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2288/head:pull/2288

PR: https://git.openjdk.java.net/jdk/pull/2288