RFR: 8371922: Remove unused NonblockingQueue class

[Coleen Phillimore]

On Fri, 14 Nov 2025 18:43:04 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this trivial change that removes the unused NonblockingQueue
> utility class and its associated gtests.
> 
> Testing: mach5 tier1

Thank you. I tried to use this once because it sounded cool but it didn't solve my problem iirc.

It is a trivial change.

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Marked as reviewed by coleenp (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28330#pullrequestreview-3466602949
PR Comment: https://git.openjdk.org/jdk/pull/28330#issuecomment-3534353318