RFR: 8371990: Remove two second delayed OOME after GC shutdown

[Stefan Karlsson]

On Mon, 17 Nov 2025 20:09:04 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

>> This function can (and will) be called without holding the `Heap_lock`. That's what the comment tried, but obviously failed, to say. :.
>> 
>> The point it tried to convey was that `VM_GC_Operation::_is_shutting_down` was initialized with the value read from `CollectedHeap::_is_shutting_down` while holding the `Heap_lock`. Subsequent code, that doesn't hold the `Heap_lock` could check `VM_GC_Operation::_is_shutting_down` to see if we skipped the GC operation because the JVM is shutting down.
>> 
>> I'll see if I can make the comment more clear.
>
> yeah, after the explanation, now comment makes sense. I didn't understand it on first pass.

I'll update the comment. Let's see if that makes things clearer.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28349#discussion_r2537944274