RFR: 8366970: CPUTimeUsage: Add comment about usage during VM exit

[David Holmes]

On Fri, 5 Sep 2025 10:06:32 GMT, Jonas Norlinder <duke at openjdk.org> wrote:

> Some of the methods in CPUTimeUsage make a query on the underlying threads. Calling those methods during VM exit is therefore unsafe. This PR adds a comment to provide clarification.

If the methods could be unsafe surely they should be checking for that, or else ensuring they are not used in unsafe contexts.

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PR Review: https://git.openjdk.org/jdk/pull/27115#pullrequestreview-3195241431