use linked hashmap

Signed-off-by: xinyual <xinyual@amazon.com>

Author: xinyual

core/src/main/java/org/opensearch/sql/planner/physical/DedupeOperator.java

@@ -7,6 +7,7 @@
 
 import com.google.common.collect.ImmutableList;
 import java.util.Collections;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -131,7 +132,7 @@ public boolean keep(ExprValue value) {
   @RequiredArgsConstructor
   static class Deduper<K> {
     private final BiFunction<Map<K, Integer>, K, Integer> seenFirstTime;
-    private final Map<K, Integer> seenMap = new ConcurrentHashMap<>();
+    private final Map<K, Integer> seenMap = new LinkedHashMap<>();
 
     /** The Historical Deduper monitor the duplicated element with all the seen value. */
     public static <K> Deduper<K> historicalDeduper() {