ci: add randomized matrix for better test coverage

[vlsi]

See https://github.com/vlsi/github-actions-random-matrix

Motivation and Context

This enables testing with different Java distributions, Java versions, Locales, Time Zones, etc.

Open issues so far:

• Spock does not work in tr_TR locale: Unrecognized block label: given @ line 31, column 13. spockframework/spock#1414 (reproducer PR ci: add randomized test matrix for better test coverage spockframework/spock#1415)

• Support ParallelExecutionConfigurationStrategy with Turkish locale junit-team/junit5#2890

• Avoid relying on item.hashCode() for Map and Collection properties #5923

• CSVDataSet might produce wrong results in SHARE_GROUP or SHARE_THREAD modes as it relies on System.identityHashCode uniqueness for ThreadGroup and Thread #5925

• same hashcode jobs fail with. Fixed by moving HashTree to IdentityHashMap and moving Map<TestElement, .. to IdentityHashMap as well

  ERROR: unexpected output for BUG_62847.csv:
    - expected 247 bytes, /Users/runner/work/jmeter/jmeter/bin/testfiles/BUG_62847.csv
    + actual 86 bytes, /Users/runner/work/jmeter/jmeter/bin/BUG_62847.csv
  @@ -1,7 +1,2 @@
   label,responseCode,responseMessage,threadName,success
  -SuccessLoop,200,OK,TG 1-1,true
  -DS_after_loop,200,OK,TG 1-1,true
  -SuccessWhile,200,OK,TG 2-1,true
  -DS_after_while,200,OK,TG 2-1,true
  -Success_FEC,200,OK,TG 3-1,true
  -DS_after_fec,200,OK,TG 3-1,true
  +DS_after_fec,200,OK,TG 1-1,true
  ERROR: unexpected output for BUG_62847.xml:
    - expected 480 bytes, /Users/runner/work/jmeter/jmeter/bin/testfiles/BUG_62847.xml
    + actual 149 bytes, /Users/runner/work/jmeter/jmeter/bin/BUG_62847.xml
  @@ -1,10 +1,5 @@
   <?xml version="1.0" encoding="UTF-8"?>
   <testResults version="1.2">
  -<sample s="true" lb="SuccessLoop" rc="200" rm="OK" tn="TG 1-1"/>
  -<sample s="true" lb="DS_after_loop" rc="200" rm="OK" tn="TG 1-1"/>
  -<sample s="true" lb="SuccessWhile" rc="200" rm="OK" tn="TG 2-1"/>
  -<sample s="true" lb="DS_after_while" rc="200" rm="OK" tn="TG 2-1"/>
  -<sample s="true" lb="Success_FEC" rc="200" rm="OK" tn="TG 3-1"/>
  -<sample s="true" lb="DS_after_fec" rc="200" rm="OK" tn="TG 3-1"/>
  +<sample s="true" lb="DS_after_fec" rc="200" rm="OK" tn="TG 1-1"/>

• Java 8 + same hashcode fails at :src:dist:processSiteXslt with VerifyError. I'm inclined to skip processSiteXslt when building with Java8 and same hashcode. We might retry if the bug is solved when xalan is updated.

  Error: Execution failed for task ':src:dist:processSiteXslt':
  : java.lang.VerifyError: (class: website_style, method: issue_separator signature: (Lcom/sun/org/apache/xalan/internal/xsltc/DOM;Lcom/sun/org/apache/xml/internal/dtm/DTMAxisIterator;Lcom/sun/org/apache/xml/internal/serializer/SerializationHandler;I)V) Illegal target of jump or branch
  at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:109)
  Caused by: java.lang.VerifyError: (class: website_style, method: issue_separator signature: (Lcom/sun/org/apache/xalan/internal/xsltc/DOM;Lcom/sun/org/apache/xml/internal/dtm/DTMAxisIterator;Lcom/sun/org/apache/xml/internal/serializer/SerializationHandler;I)V) Illegal target of jump or branch
      at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.getTransletInstance(TemplatesImpl.java:455)
      at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.newTransformer(TemplatesImpl.java:486)
  

[codecov-commenter]

Codecov Report

Merging #693 (f97d21a) into master (af7fc4d) will increase coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #693   +/-   ##
=========================================
  Coverage     55.59%   55.59%           
  Complexity    10336    10336           
=========================================
  Files          1059     1059           
  Lines         65045    65045           
  Branches       7399     7399           
=========================================
+ Hits          36160    36161    +1     
  Misses        26336    26336           
+ Partials       2549     2548    -1     

Impacted Files	Coverage Δ
...n/java/org/apache/jmeter/reporters/Summariser.java	90.07% <0.00%> (-0.77%)	⬇️
...a/org/apache/jmeter/timers/PoissonRandomTimer.java	78.37% <0.00%> (+5.40%)	⬆️

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[vlsi]

I'm going to merge this PR shortly unless there are objections.
An alternative #5727 is not dramatically smaller, and it breaks backward compatibility.

It looks like external users have much fewer usages for Map<TestElement, ...> than JMeter core, and TestElement#equals was probably used much more often for "comparing contents" in plugin code.

Unfortunately, the PR adds new usages of synchronizedMap, so we might need to replace them later. I believe they should not be dramatic