Tests SensorEventQueue I/O when the queue is full.
Reduced debug logging in multihal.

Change-Id: I30e80630ce5d97776c53f26d6096ef59b9b2f35a
diff --git a/modules/sensors/SensorEventQueue.h b/modules/sensors/SensorEventQueue.h
index 969d018..11e1f41 100644
--- a/modules/sensors/SensorEventQueue.h
+++ b/modules/sensors/SensorEventQueue.h
@@ -69,7 +69,8 @@
     void dequeue();
 
     // Blocks until space is available. No-op if there is already space.
-    void waitForSpace(pthread_mutex_t* mutex);
+    // Returns true if it had to wait.
+    bool waitForSpace(pthread_mutex_t* mutex);
 };
 
 #endif // SENSOREVENTQUEUE_H_