Under j2cl, make CollectorTester work. Previously, it was present but failed at runtime.

RELNOTES=`collect`: Under j2cl, made `CollectorTester` work. Previously, it was present but failed at runtime.
PiperOrigin-RevId: 534163401

Author: cpovirk

guava-testlib/src/com/google/common/testing/CollectorTester.java

@@ -24,7 +24,6 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.EnumSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.BiPredicate;
@@ -159,7 +158,7 @@ public final CollectorTester<T, A, R> expectCollects(R expectedResult, T... inpu
   }
 
   private void doExpectCollects(R expectedResult, List<T> inputs) {
-    for (CollectStrategy scheme : EnumSet.allOf(CollectStrategy.class)) {
+    for (CollectStrategy scheme : CollectStrategy.values()) {
       A finalAccum = scheme.result(collector, inputs);
       if (collector.characteristics().contains(Collector.Characteristics.IDENTITY_FINISH)) {
         assertEquivalent(expectedResult, (R) finalAccum);