RFR: 8328866: Add raw monitor rank support to the debug agent. [v6]

[Alex Menkov]

On Mon, 13 May 2024 18:32:45 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> FWIW Deleting monitors is a tricky business and needs to be done with great care. You have to ensure all threads using the monitor are completely done with it. Simply locking it first to check it is "unused" is not sufficient.
>
> This is probably the reason that the debug agent only destroys one of the 20 or so monitors it creates. I'm not sure how it got to that point. It may have destroyed more at one point but there were issues, and only one survived destruction without issue.

If debugger attaches to the debuggee, detaches and re-attaches again, are the monitors recreated again?
(with rankedMonitor you added an assert if `DebugRawMonitor::monitor` is not null)

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PR Review Comment: https://git.openjdk.org/jdk/pull/19044#discussion_r1599125113