Review request for JMC-6158: Adding JfrAttribute for event type id

[Guru]

+1, Changes looks good to me. 

+nit : If possible modify the text "The identifier for the event type of the event” (Three `the` in the sentence).

Thanks,
Guru
> On 04-Oct-2018, at 4:06 AM, Marcus Hirt <marcus.hirt at oracle.com> wrote:
> 
> Hi all,
> 
> Please review this fix to provide a JfrAttribute for event type id.
> 
> Jira:   https://bugs.openjdk.java.net/browse/JMC-6158
> Webrev: http://cr.openjdk.java.net/~hirt/JMC-6158/webrev.01/
> 
> Kind regards,
> Marcus
> 
>