RFR: 8278241: Implement JVM SpinPause on linux-aarch64

[Andrew Haley]

On Fri, 10 Dec 2021 21:07:13 GMT, Evgeny Astigeevich <duke at openjdk.java.net> wrote:

> @nick-arm @theRealAph @stooart-mon Hi, could you have a look please?

This is way too complicated. I'd use `MacroAssembler::spin_wait()` to generate a stub and call it from `SpinPause`.

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PR: https://git.openjdk.java.net/jdk/pull/6803