RFR: 8315950: Shenandoah: Improvements to ShenandoahInitLogger [v2]

[William Kemper]

> Changes to ShenandoahInitLogger:
> * Use macro to simplify reporting of sizes
> * Separate heap reporting from gc-specific reporting
> 
> Call the init logger from a virtual method to facilitate isolation of different gc modes.

William Kemper 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 'jdk/master' into init-logger-improvements
 - Improve ShenandoahInitLogger

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/15646/files
  - new: https://git.openjdk.org/jdk/pull/15646/files/e4f2c107..1428fded

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15646&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15646&range=00-01

  Stats: 5823 lines in 132 files changed: 3755 ins; 1311 del; 757 mod
  Patch: https://git.openjdk.org/jdk/pull/15646.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15646/head:pull/15646

PR: https://git.openjdk.org/jdk/pull/15646