RFR: 8225354: serviceability/jvmti/ModuleAwareAgents/ThreadStart failed with Didn't get ThreadStart events in VM early start phase! [v2]

[Serguei Spitsyn]

> The test incorrectly expects that some system threads must be started in the `early JVMTI_PHASE_START` phase. However, there is a race here and it is possible that the `JVMTI_PHASE_LIVE` phase is reached before any system thread has been started. The fix is to wait for the first `THREAD_START` event at the `VM_INIT` event.
> 
> The update includes some other changes and minor refactoring:
>  - the file `libMAAThreadStart.c` has been renamed to `libMAAThreadStart.cpp`
>  - the test library `jvmti_common.hpp` is used where it is possible
>  - static variable `printdump` has been removed
>  - the static block with `loadLibrary` has been removed from the `MAAThreadStart.java`
>  
>  Testing:
>   - ran the modified test locally
>   - TBD: submit mach5 tiers 1-5

Serguei Spitsyn has updated the pull request incrementally with two additional commits since the last revision:

 - corrected the Copyright line
 - small corrections and indentation fixes

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/25948/files
  - new: https://git.openjdk.org/jdk/pull/25948/files/360d911f..2d7840f1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25948&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25948&range=00-01

  Stats: 66 lines in 1 file changed: 2 ins; 0 del; 64 mod
  Patch: https://git.openjdk.org/jdk/pull/25948.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25948/head:pull/25948

PR: https://git.openjdk.org/jdk/pull/25948