Some builtin functions are actually foreign

[aakoshh]

Aim

Tried to implement the bigint functions (part of the BlackBoxFunc family) as foreign in ##6551 , but they are marked as #[builtin] in Noir.

Expected Behavior

Dispatching a builtin function to Interpreter::call_builtin should handle it, while foreign functions should go to Interpreter::call_foreign.

Bug

There is no actual bug at the moment because there are redirects in the interpreter [1, 2], but it's a bit confusing.

To Reproduce

Workaround

None

Workaround Description

The redirect in the code from builtin to foreign handles the mislabeling.

Additional Context

No response

Project Impact

None

Blocker Context

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Nargo Version

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NoirJS Version

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Proving Backend Tooling & Version

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Would you like to submit a PR for this Issue?

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Support Needs

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