RFR: 8364973: Add JVMTI stress testing mode

[Leonid Mesnik]

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.

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Commit messages:
 - problemlist and exclusion fiexd.
 - fixed IR framework
 - Merge branch 'master' of https://github.com/openjdk/jdk into jvmti-stress-agent
 - fixed small issues
 - Revert "updated struct to c++"
 - Merge branch 'master' of https://github.com/openjdk/jdk into jvmti-stress-agent
 - fixed vm death
 - updated struct to c++
 - lib updated
 - more fixes
 - ... and 7 more: https://git.openjdk.org/jdk/compare/7e484e2a...cb9c6457

Changes: https://git.openjdk.org/jdk/pull/26360/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26360&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364973
  Stats: 1175 lines in 6 files changed: 1173 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26360.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26360/head:pull/26360

PR: https://git.openjdk.org/jdk/pull/26360