RFR: 8273300: Check Mutex ranking during a safepoint [v3]

[Coleen Phillimore]

On Mon, 13 Sep 2021 21:04:32 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This change checks lock ranking during a safepoint.  For some reason, safepoint checking was excluded, probably from the days where Safepoint_lock and Threads_lock were used.
>> Because of checking during a safepoint, some locks had to get lower ranks.  The CR has the details of which locks these were.  The Service_lock complicates things because it's held during oops_do, which may take out other G1 locks.
>> This was built and tested with Shenandoah.  Thanks to @zhengyu123 for the changes in Shenandoah.
>> Tests run tier1-8.
>
> Coleen Phillimore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
> 
>  - Merge branch 'master' into checkrank
>  - Fix Shenandoah mismerge
>  - 8273300: Check Mutex ranking during a safepoint

I just remerged from master and a couple of copyright updates leaked in from my script (which I shouldn't have used).

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PR: https://git.openjdk.java.net/jdk/pull/5467