[crac] RFR: Propagating CRaC event to JVMTI agents [v3]

[Roman Marchenko]

On Tue, 21 Nov 2023 19:42:59 GMT, Roman Marchenko <rmarchenko at openjdk.org> wrote:

>> This change implements propagation of CRaC events to JVMTI.
>> 
>> - New JVMTI extension events are introduced - `EXT_EVENT_CRAC_BEFORE_CHECKPOINT` and `EXT_EVENT_CRAC_AFTER_RESTORE`.
>> - JVMTI agents should subscribe/unsubscribe to the events using `SetExtensionEventCallback` JVMTI method. 
>>   - Setting/unsetting a callback will enable/disable sending an appropriate event to an agent, i.e. there is no need to additionally call `SetEventNotificationMode` method by an agent.
>>   - See `test/jdk/jdk/crac/jvmtiEvents/libCracJvmtiAgent.c` for an example of CRaC-ready JVMTI agent
>
> Roman Marchenko has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed test

@AntonKozlov 
Hi 
Could you continue the review, please?

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PR Comment: https://git.openjdk.org/crac/pull/143#issuecomment-1860576643