tests: Reduce numbers of init and mutate calls in StressTest

This pepares for follow-up changes which will roughly double the runtime
of this test.

Author: fmeum

src/test/java/com/code_intelligence/jazzer/mutation/mutator/StressTest.java

@@ -89,8 +89,8 @@
 import org.junit.jupiter.params.provider.MethodSource;
 
 public class StressTest {
-  private static final int NUM_INITS = 500;
-  private static final int NUM_MUTATE_PER_INIT = 100;
+  private static final int NUM_INITS = 400;
+  private static final int NUM_MUTATE_PER_INIT = 80;
   private static final double MANY_DISTINCT_ELEMENTS_RATIO = 0.5;
 
   private enum TestEnumTwo {
@@ -386,7 +386,7 @@ public static Stream<Arguments> protoStressTestCases() {
         arguments(
             new TypeHolder<@NotNull MapField3>() {}.annotatedType(),
             "{Builder.Map<Integer,String>} -> Message",
-            distinctElementsRatio(0.47),
+            distinctElementsRatio(0.46),
             manyDistinctElements()),
         arguments(
             new TypeHolder<@NotNull MessageMapField3>() {}.annotatedType(),