RFR: 8272447: Remove 'native' ranked Mutex [v3]

[David Holmes]

On Mon, 23 Aug 2021 12:17:59 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> The SharedDecoder lock is used during crash reporting and so could potentially be taken whilst any other lock is held. While we special case the use of the Decoder in the initial error reporting thread, by not taking the lock due to the deadlock potential, it will still be taken by threads that encounter a secondary error. That is what makes this lock "special".
>
> That's why it's ranking is very low, below tty.  If we think it should not participate in lock ranking for deadlock detection we can make it a PlatformMutex, but I don't see any evidence that this is needed.

I took a closer look at this one and I was wrong about its use. The decoder lock won't be taken when a secondary error occurs as we would not reach any code that tries to use it in that case.

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PR: https://git.openjdk.java.net/jdk/pull/5116