RFR: JDK-8030957 - AIX: Implement OperatingSystemMXBean.getSystemCpuLoad() and .getProcessCpuLoad() on AIX [v3]

[Suchismith Roy]

> JBS Issue : [JDK-8030957](https://bugs.openjdk.org/browse/JDK-8030957)
> 
> These two methods should be implemented in src/aix/native/sun/management/AixOperatingSystem.c (which has to be created).
> 
> getProcessCpuLoad() can be probably implemented in the same way like on Solaris be reading /proc/self/psinfo
> 
> For getSystemCpuLoad() we'll probalby have to use 'perfstat_cpu_total()' from libperf (see http://publib.boulder.ibm.com/infocenter/pseries/v5r3/topic/com.ibm.aix.prftools/doc/prftools/prftools07.htm#wq407)
> 
> Once this issue has been resolved you should not forget to remove the two excludes from jdk/test/ProblemList.txt:
> 
> com/sun/management/OperatingSystemMXBean/GetProcessCpuLoad.java aix-all
> com/sun/management/OperatingSystemMXBean/GetSystemCpuLoad.java aix-all

Suchismith Roy has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - Merge branch 'master' into cpuprocessload
 - Merge branch 'master' into cpuprocessload
 - Update UnixOperatingSystem.c
 - Merge branch 'openjdk:master' into cpuprocessload
 - cleanup
 - system cpu load
 -  restore problem list
 - cpu process load

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

Changes: https://git.openjdk.org/jdk/pull/25332/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25332&range=02
  Stats: 79 lines in 2 files changed: 73 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/25332.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25332/head:pull/25332

PR: https://git.openjdk.org/jdk/pull/25332