Make adjustments to even distribution test to reduce failures

components/service/experiments/src/test/java/mozilla/components/service/experiments/ExperimentEvaluatorTest.kt

@@ -481,11 +481,18 @@ class ExperimentEvaluatorTest {
             f.call(experimentEvaluator, context) as Int
         }
 
+        distribution
+            .groupingBy { it }
+            .eachCount()
+            .forEach {
+                Assert.assertTrue(it.value in 0..9)
+            }
+
         distribution
             .groupingBy { it / 10 }
             .eachCount()
             .forEach {
-                Assert.assertTrue(it.value in 0..25)
+                Assert.assertTrue(it.value in 0..29)
             }
 
         distribution