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

@@ -38,12 +38,12 @@ dataset_info:
   - name: answer_right_ending
     dtype: int32
   splits:
-  - name: test
-    num_bytes: 613184
-    num_examples: 1871
   - name: validation
     num_bytes: 614084
     num_examples: 1871
+  - name: test
+    num_bytes: 613184
+    num_examples: 1871
   download_size: 0
   dataset_size: 1227268
 - config_name: '2018'