[crac] RFR: 8361090: [CRaC] Make dev engines less confusing

[Timofei Pushkin]

On Tue, 1 Jul 2025 10:24:59 GMT, Timofei Pushkin <tpushkin at openjdk.org> wrote:

>> src/java.base/linux/native/pauseengine/pauseengine.c line 68:
>> 
>>> 66:         fclose(pidfile);
>>> 67: 
>>> 68:         printf(PAUSEENGINE "pausing the process, restore in another process to unpause it\n");
>> 
>> I would rather see all these logging messages going into `stderr`.
>
> Warp prints its "Checkpoint successful" message to stout IIRC, then this should.go there too since it is essentially the same thing. We can make it disable-able via `-XX:CRaCEngineOptions=args=-quiet` for example.

NVMD, Warp actually prints to stderr, I was mistaken

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PR Review Comment: https://git.openjdk.org/crac/pull/239#discussion_r2177512940