RFR: 8343249: [Windows] Implement SpinPause [v4]

[Saint Wesonga]

On Thu, 15 Jan 2026 23:31:51 GMT, David Holmes <dholmes at openjdk.org> wrote:

> I thought I saw direct calls to `spin_wait` elsewhere in the code. ./cpu/aarch64/aarch64.ad

Yes, those happen e.g. with C2 and they can be influenced with those command line flags. However, it would be good to also respect them in other locations e.g. to use a speculation barrier instruction in [ObjectMonitor::try_spin](https://github.com/openjdk/jdk/blob/b6b337926d5f13ee2bca12ea94530ea59911ff2f/src/hotspot/share/runtime/objectMonitor.cpp#L2448) as well.

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PR Comment: https://git.openjdk.org/jdk/pull/21781#issuecomment-3757388057