ART: Log all monitor operations to systrace

Add a VLOG option ("-verbose:systrace-locks") to log all monitor
operations to systrace. This requires non-fastpath thread
entrypoints, and ATRACE tags for locking and unlocking.

Do a bit of cleanup to the entrypoint initialization to share
common setup.

Bug: 28423466

(cherry picked from commit fc6898769ae1ef91ec3e41c0a273401213cb82cd)

Change-Id: Ie67e4aa946ec15f8fcf8cb7134c5d3cff0119ab3
diff --git a/runtime/base/logging.h b/runtime/base/logging.h
index 97280c3..3b5b8b5 100644
--- a/runtime/base/logging.h
+++ b/runtime/base/logging.h
@@ -56,6 +56,7 @@
   bool threads;
   bool verifier;
   bool image;
+  bool systrace_lock_logging;  // Enabled with "-verbose:sys-locks".
 };
 
 // Global log verbosity setting, initialized by InitLogging.