RFR: JDK-8315026: java/lang/ProcessHandle/TreeTest.java fails intermittent on AIX in TreeTest.test5 [v5]

[Joachim Kern]

> We see rather often failures in java/lang/ProcessHandle/TreeTest.java on AIX in TreeTest.test5.
> The reason is: Previously the implementation based on the /proc file system lead to double pids in the child list; at least intermittent. Using the API getprocs64() instead I was able to eliminate those double pids (and increase the performance by a factor of 4). Otherwise we would have to add an algorithm to filter out the doubles after creating the raw list.

Joachim Kern has updated the pull request incrementally with one additional commit since the last revision:

  revise of the function comment and some other proposals

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16051/files
  - new: https://git.openjdk.org/jdk/pull/16051/files/986ff9a0..55e20035

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16051&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16051&range=03-04

  Stats: 40 lines in 2 files changed: 18 ins; 8 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/16051.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16051/head:pull/16051

PR: https://git.openjdk.org/jdk/pull/16051