…try estimation (colmap#3492)
This PR adds a `random_seed` parameter to `RANSACOptions` for
deterministic results in multithreaded environments.
- `random_seed = -1` (default) preserves the original nondeterministic
behavior.
- Setting it to a fixed value makes estimation deterministic and
reproducible.
- Currently applied and tested only in `TwoViewGeometry` estimation.
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Co-authored-by: StonerLing <sisyphus.stoner@outlook.com>