test_options.rnc does not use the spud base language for python code

Since the test xmls predate the use of schemas test_options.rnc does not use standard spud base language elements to describe python code and hence ends up depending on fluidity specific hacks in diamond.

Fixing this would require updating testharness to look for the python strings in the right place as well as updating the schema itself (and then removing the hacks from diamond, see separate bug report in spud).