Fix flaky multimatchquerybuildertests (#18013)

Signed-off-by: Harsha Vamsi Kalluri <harshavamsi096@gmail.com>

Author: harshavamsi

server/src/test/java/org/opensearch/index/query/MultiMatchQueryBuilderTests.java

@@ -55,6 +55,7 @@
 import org.opensearch.index.query.MultiMatchQueryBuilder.Type;
 import org.opensearch.index.search.MatchQuery;
 import org.opensearch.lucene.queries.ExtendedCommonTermsQuery;
+import org.opensearch.search.approximate.ApproximateScoreQuery;
 import org.opensearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
@@ -198,7 +199,8 @@ protected void doAssertLuceneQuery(MultiMatchQueryBuilder queryBuilder, Query qu
                     instanceOf(PhraseQuery.class),
                     instanceOf(PointRangeQuery.class),
                     instanceOf(IndexOrDocValuesQuery.class),
-                    instanceOf(PrefixQuery.class)
+                    instanceOf(PrefixQuery.class),
+                    instanceOf(ApproximateScoreQuery.class)
                 )
             )
         );