SERVER-43945 Expose out of order latch acquisitions in serverStatus

This review does several related things:
- Modifies the Mutex type to have one Identity object per invocation context
- Adds a latchAnalysis field to serverStatus
- Officially turns on CI-only failure for acq level violations
- Changes a few acq level declarations to be more permissive

1 files changed, 3 insertions, 1 deletions

diff --git a/src/mongo/util/background.cpp b/src/mongo/util/background.cpp
index 9dff4675fc7..6951bf86681 100644
--- a/src/mongo/util/background.cpp
+++ b/src/mongo/util/background.cpp
@@ -81,7 +81,9 @@ private:
     void _runTask(PeriodicTask* task);
 
     // _mutex protects the _shutdownRequested flag and the _tasks vector.
-    Mutex _mutex = MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(0), "PeriodicTaskRunner::_mutex");
+    Mutex _mutex = MONGO_MAKE_LATCH(
+        // This mutex is held around task execution HierarchicalAcquisitionLevel(0),
+        "PeriodicTaskRunner::_mutex");
 
     // The condition variable is used to sleep for the interval between task
     // executions, and is notified when the _shutdownRequested flag is toggled.