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

@@ -92,12 +92,12 @@ dataset_info:
           0: not-toxic
           1: toxic
   splits:
-  - name: test
-    num_bytes: 216297
-    num_examples: 2100
   - name: train
     num_bytes: 1709560
     num_examples: 16800
+  - name: test
+    num_bytes: 216297
+    num_examples: 2100
   - name: validation
     num_bytes: 212153
     num_examples: 2100