RFR: 8307057 JFR: Enable -XX:+DebugNonSafepoints when JFR starts

[Andrei Pangin]

On Thu, 25 May 2023 10:35:01 GMT, Erik Gahlin <egahlin at openjdk.org> wrote:

> Could I have review of a change that enables DebugNonSafepoints when JFR starts.
> 
> Testing: tier1, tier2, tier3, tier4
> 
> Thanks
> Erik

Turning on `DebugNonSafepoints` automatically when JFR is enabled at startup makes total sense. However, turning it on automatically at runtime can be confusing: previously compiled methods will not have debug info, so the profile may be still inaccurate, while JMC will no longer hint user about potential inaccuracy since it will see `DebugNonSafepoints=true`.

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PR Review: https://git.openjdk.org/jdk/pull/14147#pullrequestreview-1444133070