RFR: JDK-8272703: StressSeed should be set via FLAG_SET_ERGO

[Tobias Hartmann]

On Tue, 21 Sep 2021 08:38:57 GMT, Tobias Holenstein <github.com+71546117+tobiasholenstein at openjdk.org> wrote:

> Set the `StressSeed` (added by JDK-8252219) via `FLAG_SET_ERGO` if the seed is generated by the VM (i.e., not set via the command line). This way, `StressSeed` will be added to the "[Global flags]" section of the hs_err file on crash and can be used to reproduce the issue.
> 
> If `RepeatCompilation` is on and no `StressSeed` is set, a new `StressSeed` is generated for every compilation. The reason for this is that some Bugs are only triggered intermittent, because they depend on the `StressSeed`.

Looks good to me.

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Marked as reviewed by thartmann (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5599