Surface recon determinism

[ClePol]

Summary

This PR contains

1. An improvement of the surface pipeline to make surface reconstruction deterministic by setting fixed seeds / deterministic options across the relevant surface-generation steps.
2. A fix for a false failure in the surfaceRAS header sanity check after mri_mc: the old tr | grep -q pipeline could report failure due to SIGPIPE even when mris_info showed valid vertex locs : surfaceRAS.

Testing

End-to-end pipeline run before and after changes on 5 cases.