Add "-p precedence over -np" test case (to fail)

As of this writing, this test should fail.

This merge request is related to #379 (closed) and fixing #379 (closed) should make this test succeed.

Because I'm relatively busy and very new to wget2 code, I cannot write a patch to fix #379 (closed) for a while. I apologize for that.

Approver's checklist:

• The author has submitted the FSF Copyright Assignment and is listed in AUTHORS
• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent with existing code
• This feature/change has adequate documentation added (if appropriate)
• No obvious mistakes / misspelling in the code