[TEST] removed REST test that checks for delete by query shard failures

The clients return an exception in case of failure and not the whole json response containing failures, thus this tests can only work with the Java REST tests runner

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

@@ -40,24 +40,3 @@
         index: test_1
 
   - match:  { count:     2  }
-
----
-"Delete by query failures":
-  - do:
-      index:
-          index:  test_1
-          type:   test
-          id:     1
-          body:   { foo: bar }
-
-  - do:
-      catch: request
-      delete_by_query:
-        index:  test_1
-        body:
-          query:
-            does_not_exist:
-              foo: bar
-
-  - length: { _indices.test_1._shards.failures: 5 }
-