[io/Stats] only record steal attempts if stats are enabled

emper/io/Stats.hpp

@@ -211,7 +211,10 @@ class Stats {
 		abort();
 	}
 
-	inline void recordStealAttempt() { ATOMIC_INC_RELAXED(steal_attempts); }
+	inline void recordStealAttempt() {
+		RETURN_IF_NO_STATS();
+		ATOMIC_INC_RELAXED(steal_attempts);
+	}
 
 	// running mean calculation taken from
 	// https://math.stackexchange.com/questions/106700/incremental-averageing