Fix the logic of getting maxSuccessQps in StatisticNode (#1196)

sentinel-core/src/main/java/com/alibaba/csp/sentinel/node/StatisticNode.java

@@ -213,7 +213,8 @@ public class StatisticNode implements Node {
 
     @Override
     public double maxSuccessQps() {
-        return rollingCounterInSecond.maxSuccess() * rollingCounterInSecond.getSampleCount();
+        return (double) rollingCounterInSecond.maxSuccess() * rollingCounterInSecond.getSampleCount()
+                / rollingCounterInSecond.getWindowIntervalInSec();
     }
 
     @Override