This PR adds ranked monitor support to the debug agent. The debug agent has a large number of monitors, and it's really hard to know which order to grab them in, and for that matter which monitors might already be held at any given moment. By imposing a rank on each monitor, we can check to make sure they are always grabbed in the order of their rank. Having this in place when I was working on [JDK-8324868](https://bugs.openjdk.org/browse/JDK-8324868) would have made it much easier to detect a deadlock that was occuring, and the reason for it. That's what motivated me to do this work
There were 2 or 3 minor rank issues discovered as a result of these changes. I also learned a lot about some of the more ugly details of the locking support in the process. Tested with the following on all supported platforms and with virtual threads: com/sun/jdi vmTestbase/nsk/jdi vmTestbase/nsk/jdb vmTestbase/nsk/jdwp Still need to run tier2 and tier5. Details of the changes follow in the first comment. ------------- Commit messages: - Fix jchecks errors - Add ranked monitor support to the debug agent. Changes: https://git.openjdk.org/jdk/pull/19044/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19044&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8328866 Stats: 591 lines in 11 files changed: 515 ins; 5 del; 71 mod Patch: https://git.openjdk.org/jdk/pull/19044.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/19044/head:pull/19044 PR: https://git.openjdk.org/jdk/pull/19044
