RFR: 8323634: Shenandoah: Document behavior of EvacOOM protocol

Fri Jan 12 14:34:39 UTC 2024

The protocol for handling OOM during evacuation is subtle and critical for correct operation.  This PR does NOT change behavior.  It provided improved documentation of existing behavior.

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

Commit messages:
 - Fix comments and white space
 - Fix typo
 - Improve documentation of how Evac-OOM Protocol works

Changes: https://git.openjdk.org/jdk/pull/17385/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17385&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323634
  Stats: 209 lines in 3 files changed: 168 ins; 0 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/17385.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17385/head:pull/17385

PR: https://git.openjdk.org/jdk/pull/17385