RFR: 8151594: Move concurrent refinement thread activation logging out of GC pause [v2]

[Kim Barrett]

> Please review this move of the thread activation logging by concurrent
> refinment threads to be within the suspendible thread set context, rather
> than before it.  This prevents the logging for the thread activation
> sometimes being intermixed with GC pause-time logging.
> 
> Testing:
> mach5 tier1

Kim Barrett 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 crt_active0
 - move thread active logging inside sts

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6551/files
  - new: https://git.openjdk.java.net/jdk/pull/6551/files/fb8f29d2..580ebc45

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6551&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6551&range=00-01

  Stats: 3989 lines in 141 files changed: 2467 ins; 1023 del; 499 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6551.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6551/head:pull/6551

PR: https://git.openjdk.java.net/jdk/pull/6551