fix small bug

Author: roberttoyonaga

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestGarbageCollectionEvents.java

@@ -31,7 +31,9 @@
 import jdk.jfr.consumer.RecordedEvent;
 import org.junit.Test;
 
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import static org.junit.Assert.assertTrue;
 
@@ -49,9 +51,10 @@ public void test() throws Throwable {
     private static void validateEvents(List<RecordedEvent> events) {
         assertTrue(events.size() > 0);
         int foundSystemGc = 0;
-        int expectedId = 0;
+        Set<Integer> ids = new HashSet<>();
         for (RecordedEvent event : events) {
-            assertTrue(expectedId == event.getInt("gcId"));
+            assertTrue(!ids.contains(event.getInt("gcId")));
+            ids.add(event.getInt("gcId"));
             assertTrue(event.getThread("eventThread").getJavaName() != null);
             assertTrue(!event.getDuration().isZero());
             assertTrue(event.getString("name") != null);
@@ -60,9 +63,7 @@ private static void validateEvents(List<RecordedEvent> events) {
             if (event.getString("cause").equals("java.lang.System.gc()")) {
                 foundSystemGc++;
             }
-            expectedId++;
         }
         assertTrue(foundSystemGc >= 3);
-        assertTrue(expectedId >= 3);
     }
 }