correct new file literal test

Author: mr-c

draft-4/conformance_test_draft-4.yaml

@@ -786,6 +786,6 @@
       class: File
       checksum: sha1$d0e04ff6c413c7d57f9a0ca0a33cd3ab52e2dd9c
       location: output.txt
-      size: 13
+      size: 18
   tool: draft-4/cat3-tool.cwl
   doc: Test file literal as input