Reorder split names

Reorder split names in the YAML metadata to be aligned with the order in the loading script.
See: https://github.com/huggingface/datasets/issues/5258

README.md

@@ -50,12 +50,12 @@ dataset_info:
           1: pos
   config_name: best2009
   splits:
-  - name: test
-    num_bytes: 10498726
-    num_examples: 2252
   - name: train
     num_bytes: 483129998
     num_examples: 148995
+  - name: test
+    num_bytes: 10498726
+    num_examples: 2252
   download_size: 13891260
   dataset_size: 493628724
 ---