Support for contention logging with ART futexes.

Remove dangerous postfix operators on AtomicInteger. Clean up the atomic stack.
Factor nanosleep into a useful shared utils.h routine.

Change-Id: I417a73007c23fe247f410f41b2fa41a717c22139
diff --git a/src/runtime.cc b/src/runtime.cc
index 2416581..4cf7d97 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -917,6 +917,7 @@
   os << "\n";
 
   thread_list_->DumpForSigQuit(os);
+  BaseMutex::DumpAll(os);
 }
 
 void Runtime::DumpLockHolders(std::ostream& os) {