patch: free argument for expectation changes sources

The tool has hard-coded a list of the known places where the job results are stored (aka failures.csv and results.csv.zst).

We saw a user case where this is a problem (!46 (closed)), and that's because in DrmCI the jobs aren't compressing the results.csv. Together with job in MesaCI that pushes the compressed and the non-compressed files, complicates this task.

There is another user case that we could think of: if one likes to specifically not process one of those two files.

This change, as the default value is it is not set is not specified until the last moment, allows some developers with knowledge of the jobs, using directly the CollateJob() object to specify the path to the file, avoiding the search feature that we use when the file starts with a star.