RFR: 8319244: implement JVMTI handshakes support for virtual threads [v4]

[Serguei Spitsyn]

On Wed, 8 Nov 2023 16:02:08 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> src/hotspot/share/prims/jvmtiEnvBase.cpp line 2416:
>> 
>>> 2414:   if (!JvmtiEnvBase::is_vthread_alive(_target_h())) {
>>> 2415:     return; // JVMTI_ERROR_THREAD_NOT_ALIVE (default)
>>> 2416:   }
>> 
>> Don't we have this check already in JvmtiHandshake::execute()? Same with the other converted functions.
>
> Good suggestion, thanks.
> I'm a little bit paranoid about terminated vthreads. :)
> Will try to get rid of it and retest all tiers.

I've removed the extra checks for `JvmtiEnvBase::is_vthread_alive()`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16460#discussion_r1396115170