Verify that the "Saved to filename 'blabla'" message is only displayed when the 'blabla' filename being used _actually_ has been specified by the server in the Content-Disposition header. Use relative path for unintended file creation postcheck.
Add a postcheck section to verify unintended file creation. Remove needless <file> checks in verify section. Renumbering where appropriate.
Currently 1356 to 1362 succeed but a write failure is logged in traceNNNN. Currently 1363 fails, so disabled for now.