RFR: 8258255: Move PtrQueue active flag to SATBMarkQueue [v3]

[Kim Barrett]

> Please review this change to the PtrQueue hierarchy, moving the support for
> "active" queues and qset to SATBMarkQueue[Set], which is the only user of
> this feature.  Other classes derived from PtrQueue[Set] currently work
> around or ignore this feature.  This change removes it from consideration
> entirely for those other classes.
> 
> Testing:
> mach5 tier1
> local (linux-x64) hotspot:tier1 with -XX:+UseShenandoahGC
> 
> In the process of doing this refactoring I noticed that some of the
> vmStructs support around PtrQueue[Set] didn't get moved from G1 to shared,
> and the G1 parts are incomplete.  Filed JDK-8258581 to address that.

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 three additional commits since the last revision:

 - Merge branch 'master' into move_active
 - tschatzl review
 - move_active

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1820/files
  - new: https://git.openjdk.java.net/jdk/pull/1820/files/dccbeb46..96fec70f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1820&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1820&range=01-02

  Stats: 1835 lines in 122 files changed: 1211 ins; 253 del; 371 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1820.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1820/head:pull/1820

PR: https://git.openjdk.java.net/jdk/pull/1820