fix: match codspeed-rust STDEV_OUTLIER_FACTOR (3.0)

Author: not-matthias

jmh-fork/jmh-core/src/main/java/io/codspeed/result/WalltimeBenchmark.java

@@ -5,7 +5,7 @@
 
 public class WalltimeBenchmark {
   private static final double IQR_OUTLIER_FACTOR = 1.5;
-  private static final double STDEV_OUTLIER_FACTOR = 2.0;
+  private static final double STDEV_OUTLIER_FACTOR = 3.0;
 
   private final String name;
   private final String uri;