Fix bug of JVM metrics handler and make ALS doc more accurate

[wu-sheng]

Resolves #5394, and JVM metrics handler bugs reported by @peng-yongsheng

[codecov]

Codecov Report

Merging #5400 into master will decrease coverage by 0.15%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #5400      +/-   ##
============================================
- Coverage     53.17%   53.01%   -0.16%     
+ Complexity     3219     3216       -3     
============================================
  Files           829      830       +1     
  Lines         20942    20981      +39     
  Branches       2036     2037       +1     
============================================
- Hits          11135    11124      -11     
- Misses         8899     8945      +46     
- Partials        908      912       +4     

Impacted Files	Coverage Δ	Complexity Δ
...ver/analyzer/provider/jvm/JVMSourceDispatcher.java	97.89% <100.00%> (ø)	17.00 <0.00> (ø)
.../analyzer/provider/meter/process/MeterBuilder.java	40.62% <0.00%> (-4.69%)	7.00% <0.00%> (ø%)
...nalyzer/provider/meter/process/MeterProcessor.java	57.62% <0.00%> (-3.39%)	13.00% <0.00%> (ø%)
...g/oap/server/telemetry/prometheus/BaseMetrics.java	86.66% <0.00%> (-3.34%)	8.00% <0.00%> (-1.00%)
...ng/oap/server/core/alarm/provider/RunningRule.java	45.90% <0.00%> (-1.82%)	11.00% <0.00%> (ø%)
...r/storage/plugin/influxdb/query/MetadataQuery.java	59.23% <0.00%> (-0.77%)	11.00% <0.00%> (-1.00%)
.../skywalking/amp/testcase/undertow/Application.java	0.00% <0.00%> (ø)	0.00% <0.00%> (?%)

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[peng-yongsheng]

OK

[innerpeacez]

ALS doc. LGTM