[TEST] Split delete by query tests pre-1.0 and post-1.0

See #4074 for details

rest-api-spec/test/delete_by_query/10_basic.yaml

@@ -1,5 +1,8 @@
 ---
-"Basic delete_by_query":
+"Basic delete_by_query, post 1.0":
+  - skip:
+      version: "0 - 0.999"
+      reason: "Since 1.0 the query top-level key in the body is required"
   - do:
       index:
           index:  test_1
@@ -34,6 +37,52 @@
 
   - is_true: ok
 
+  - do:
+      indices.refresh: {}
+
+  - do:
+      count:
+        index: test_1
+
+  - match:  { count:     2  }
+---
+"Basic delete_by_query, pre 1.0":
+  - skip:
+      version: "1 - 999"
+      reason: "Since 1.0 the query top-level key in the body is required"
+  - do:
+      index:
+          index:  test_1
+          type:   test
+          id:     1
+          body:   { foo: bar }
+
+  - do:
+      index:
+          index:  test_1
+          type:   test
+          id:     2
+          body:   { foo: baz }
+
+  - do:
+      index:
+          index:  test_1
+          type:   test
+          id:     3
+          body:   { foo: foo }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      delete_by_query:
+        index:  test_1
+        body:
+          match:
+            foo: bar
+
+  - is_true: ok
+
   - do:
       indices.refresh: {}