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

@@ -108,12 +108,12 @@ dataset_info:
   - name: context
     dtype: string
   splits:
-  - name: test
-    num_bytes: 341414
-    num_examples: 1283
   - name: train
     num_bytes: 2730651
     num_examples: 10269
+  - name: test
+    num_bytes: 341414
+    num_examples: 1283
   - name: validation
     num_bytes: 341592
     num_examples: 1284