RFR: 8365994: ZGC: Incorrect type signature in ZMappedCache comparator

[Joel Sikström]

On Fri, 22 Aug 2025 15:13:35 GMT, Casper Norrbin <cnorrbin at openjdk.org> wrote:

>> Hello,
>> 
>> The comparator with two IntrusiveRBNode* in ZMappedCache has the incorrent type signature. This prevents IntrusiveRBTree from using the comparator as intended during validation, resulting in it using the fallback verify function, which always returns true. This could mask potential issues in the tree structure. 
>> 
>> Testing:
>> * Manually placing an assert in the fallback verify function to see if it is used. It is no longer used with this patch.
>> * Oracle's tier 1-2
>
> Looks good!

Thank you for the reviews! @caspernorrbin @xmas92

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PR Comment: https://git.openjdk.org/jdk/pull/26904#issuecomment-3223242045