RFR: 8269914: Factor out heap printing for G1 young and full gc

[Thomas Schatzl]

On Wed, 7 Jul 2021 08:23:35 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
> can I have reviews for this change that factors out before/after heap related printing into a single scoped object to be used for both young and full gc code?
> 
> There is some minor change in order of printing of unrelated log output (COMMIT/UNCOMMIT region state changes vs. other heap printing), during full gc but since this is very low level debugging I do not see a problem to do that.
> 
> (Sorry for the trouble with open/closing this issue already: have been experimenting with the feature to base PRs on other PRs which kind-of failed a bit; rebased on tip after being able to push all dependencies, so this one should be good)
> 
> To keep JFR event sending in the correct order, this change includes JDK-8270018.
> 
> Thanks,
>   Thomas

Apologies for this recent change: due to the way I split the change containing all changes there had been a problem with JFR events getting sent out of order which some tests checked (in `jdk/jfr/event/gc/collection/*`). The event to send the age table had been sent after the "gc end" event.
This is fixed by making sure that the JFR tracer/timers are appropriately used in scoped objects as well.

Also the original change contained the output of a merge error.

Apologies. Should be all fixed now though, but I'll rerun tier1-5

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PR: https://git.openjdk.java.net/jdk/pull/4705