Assign a lower Locklevel for Mutexes used in QuasiAtomic operations.
This fixes the CompilerDriverTest on MIPS. The test was failing when
Transaction::Abort() acquired intern_table_lock_ and log_lock_
and subsequently performed QuasiAtomic operations.

Change-Id: I9fcda51221f1f298bcb5dd0e10019bd2034ab8ae
diff --git a/runtime/base/mutex.h b/runtime/base/mutex.h
index 1ba6180..81e62ab 100644
--- a/runtime/base/mutex.h
+++ b/runtime/base/mutex.h
@@ -55,6 +55,7 @@
 enum LockLevel {
   kLoggingLock = 0,
   kMemMapsLock,
+  kSwapMutexesLock,
   kUnexpectedSignalLock,
   kThreadSuspendCountLock,
   kAbortLock,