RFR: 8273147: Update and restructure TestGCLogMessages log message list [v3]

[Thomas Schatzl]

> Hi all,
> 
>   please review this change that updates the TestGCLogMessages file for more or less recently added log messages.
> 
> Test: executing test case
> 
> Thanks,
>   Thomas

Thomas Schatzl 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 five additional commits since the last revision:

 - Fix comment after accidental removal during merge
 - Merge master
 - Add messages for parallel concurrent mark start initiation phase
 - Fixes
 - Remove unused log entry

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5306/files
  - new: https://git.openjdk.java.net/jdk/pull/5306/files/21168c45..a8f27ca1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5306&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5306&range=01-02

  Stats: 3874 lines in 102 files changed: 1263 ins; 1231 del; 1380 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5306.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5306/head:pull/5306

PR: https://git.openjdk.java.net/jdk/pull/5306