[crac] RFR: Improved open file descriptors tracking [v9]

[Radim Vansa]

On Mon, 24 Apr 2023 13:27:30 GMT, Radim Vansa <duke at openjdk.org> wrote:

>> Tracks `java.io.FileDescriptor` instances as CRaC resource; before checkpoint these are reported and if not allow-listed (e.g. as opened as standard descriptors) an exception is thrown. Further investigation can use system property `jdk.crac.collect-fd-stacktraces=true` to record origin of those file descriptors.
>> File descriptors claimed in Java code are passed to native; native code checks all open file descriptors and reports error if there's an unexpected FD that is not included in the list passed previously.
>
> Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Provide more information for file descriptors

Converting to draft until #60 gets integrated.

Also note that RefQueueTest is failing (at least on my machine) because of race documented in that test.

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PR Comment: https://git.openjdk.org/crac/pull/43#issuecomment-1540461583