RFR: 8364973: Add JVMTI stress testing mode [v6]

[Magnus Ihse Bursie]

On Fri, 15 Aug 2025 04:33:59 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> The fix added JVMTI stress testing mode.
>> 
>> This mode enables stress agent that could be executed with jtreg test and help to ensure that jvmti functionality doesn't break the other JVM/JDK functionality.
>> 
>> I filed few issues and more are coming. I want to push the agent so it is possible to provide reproduces for problems uncovered by this agent.
>> 
>> The agent has 2 modes now:
>>  - regular that is compatible with most of tests including other jvmti, jdi and jdb tests
>>  - debugger, that additionally test some function requiring  solo capabilities and not compatible with debugger and some jvmti  tests 
>> 
>> The tests incompatible wiht agent (IR, CDS) and some individual tests from tier1 are excluded. There are not plans to support stable execution of all tests with agent right now. However it provokes some crashes worth to be used for exploratory testing.
>> Note, that flagless tests are excluded automatically and not executed in this mode.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   add documentation

LGTM now. Thanks!

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Marked as reviewed by ihse (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26360#pullrequestreview-3123261422