PFS test should save timing output to the baseline directory

It would be very useful if the PFS test saved timing output to the baseline directory. That way, if you have a PFS test in the test suite, you can more easily compare the current timing with the previous timing.

I'm thinking it may be hard to customize baseline generation for a single test type like this; if so, maybe we should just save the timing files for all tests. (Those files are typically fairly small.)