[jdk11u-dev] RFR: 8215624: Add parallel heap iteration for jmap –histo [v2]

[Bin Liao]

> Unclean backport, since original patch does not apply cleanly to 11u, because jmap command parameter is different between each other, and the code structure has little changed.
>  
>     8215624: Add parallel heap iteration for jmap -histo
>     8253763: ParallelObjectIterator should have virtual destructor

Bin Liao 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 parallel_heap_iter
 - 8266352: Add parallel heap iteration for jmap -histo
   
       8215624: Add parallel heap iteration for jmap histo
       8253763: ParallelObjectIterator should have virtual destructor

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

Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/127/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/127/files/a2fe90d3..d220790f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=127&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=127&range=00-01

  Stats: 24153 lines in 626 files changed: 13695 ins; 7193 del; 3265 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/127.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/127/head:pull/127

PR: https://git.openjdk.java.net/jdk11u-dev/pull/127