RFR: 8374449: Shenandoah: Leaf locks used by Shenandoah need lower ranks

[William Kemper]

Reduce the rank of `safepoint` locks and rename them to avoid confusion with `nosafepoint` ranked locks.

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Commit messages:
 - Add constant for control lock rank
 - More lock rank tweaks
 - Go even lower, don't check for safepoint when taking the locks
 - Merge remote-tracking branch 'jdk/master' into lower-controller-lock-ranks
 - Use an even lower rank
 - Lower controller lock ranks to avoid false deadlock detection

Changes: https://git.openjdk.org/jdk/pull/29333/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29333&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374449
  Stats: 7 lines in 3 files changed: 3 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/29333.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29333/head:pull/29333

PR: https://git.openjdk.org/jdk/pull/29333