SystemRule calculate process cpu usage to support application running in container

[tianhaowhu]

Describe what this PR does / why we need it

SystemRule currently use the host's cpu usage, so it doesn't support the application running in the container such as docker, etc. This PR leverage both the process cpu usage and host's cpu usage to support application running in container.

Does this pull request fix one issue?

NONE

Describe how you did it

In the SystemStatusListener, I leverage JMX to get processCpuTime, processUpTime and cpuCores(the number of cpu cores, and it is the number of cpu cores which assigned to the container if application running in container).

Then the process cpu usage can be calculated as below:
processCpuUsage := delta(processCpuTime) / delta(processUpTime) / cpuCores

After that, we can use the max value between host's cpu usage and processCpuUsage to check the system status

Describe how to verify it

Special notes for reviews

[sczyh30]

Hi, thanks for contributing. Could you please sign the CLA here? And please make sure the email of your commits match your GitHub email. You may refer to the instruction here, or rebase your commits with the correct email.

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感谢贡献，请将 commit 对应的 email 调整成与 GitHub 的 email 相匹配并 确认一下 CLA。

[sczyh30]

And could you please illustrate your design (and how you did it) in the PR description?

[codecov-io]

Codecov Report

Merging #1204 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #1204      +/-   ##
============================================
+ Coverage     43.03%   43.05%   +0.01%     
+ Complexity     1570     1568       -2     
============================================
  Files           337      337              
  Lines          9877     9890      +13     
  Branches       1332     1332              
============================================
+ Hits           4251     4258       +7     
- Misses         5099     5102       +3     
- Partials        527      530       +3

Impacted Files	Coverage Δ	Complexity Δ
...sp/sentinel/slots/system/SystemStatusListener.java	57.5% <100%> (+20.46%)	3 <0> (ø)	⬇️
...ava/com/alibaba/csp/sentinel/node/ClusterNode.java	96.55% <0%> (-3.45%)	10% <0%> (-1%)
...a/csp/sentinel/slots/statistic/base/LeapArray.java	67.32% <0%> (-2.98%)	33% <0%> (-1%)
...tinel/slots/block/flow/param/ParamFlowChecker.java	52.7% <0%> (-2.71%)	28% <0%> (-1%)
...m/alibaba/csp/sentinel/log/DateFileLogHandler.java	57.57% <0%> (+3.03%)	7% <0%> (+1%)	⬆️

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[tianhaowhu]

And could you please illustrate your design (and how you did it) in the PR description?

sure

[CLAassistant]

All committers have signed the CLA.

[jasonjoo2010]

Oh this PR was submitted months ago. Is the submitter still here?

[jasonjoo2010]

LGTM

[jasonjoo2010]

Thanks for contribution and look forward for more!

[brucelwl]

为什么不直接用double processCpuLoad = osBean.getProcessCpuLoad();获取呢?