Modify all the plans to use ONE_TO_ONE_EXCHANGE for result distribution operator.
diff --git a/asterix-app/src/test/resources/optimizerts/results/btree-index/btree-primary-21.plan b/asterix-app/src/test/resources/optimizerts/results/btree-index/btree-primary-21.plan
index 50b1c04..6f13ebb 100644
--- a/asterix-app/src/test/resources/optimizerts/results/btree-index/btree-primary-21.plan
+++ b/asterix-app/src/test/resources/optimizerts/results/btree-index/btree-primary-21.plan
@@ -1,5 +1,5 @@
 -- DISTRIBUTE_RESULT  |PARTITIONED|
-  -- RANDOM_MERGE_EXCHANGE  |PARTITIONED|
+  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
     -- STREAM_PROJECT  |PARTITIONED|
       -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
         -- BTREE_SEARCH  |PARTITIONED|