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

@@ -81,12 +81,12 @@ dataset_info:
           2: Business
           3: Sci/Tech
   splits:
-  - name: test
-    num_bytes: 1879478
-    num_examples: 7600
   - name: train
     num_bytes: 29817351
     num_examples: 120000
+  - name: test
+    num_bytes: 1879478
+    num_examples: 7600
   download_size: 31327765
   dataset_size: 31696829
 ---