parfile_test should use test size/timeout

[mjansche]

When running a par_test, the native py_test uses size/timeout as specified in kwargs. But the corresponding parfile_test ignores those, defaulting to size="moderate". Not a major issue, but impacts e.g. smoke testing when I want to run small/short tests first: in a par_test marked as size="small" the native py_test gets run but the corresponding parfile_test gets filtered out due to its larger size. Expected instead: The parfile_test gets run using the size/timeout as specified in the par_test.