as_field and from_field are not implemented in the interpreter

[asterite]

Aim

This code:

pub global x: U128 = U128::from_integer(1);

fn main() {}

and this code:

pub global x: Field = U128::from_hex("0x0").to_integer();

fn main() {}

Expected Behavior

The above snippets should compile.

Bug

They fail respectively with these errors:

error: Comptime evaluation for builtin function 'as_field' is currently unimplemented
    ┌─ std/uint128.nr:143:17
    │
143 │         let f = crate::as_field(i);
    │                 ------------------

and

error: Comptime evaluation for builtin function 'as_field' is currently unimplemented
    ┌─ std/lib.nr:102:23
    │
102 │     crate::from_field(crate::as_field(x) + crate::as_field(y))
    │                       ------------------

This is because we now interpret globals.

To Reproduce

Workaround

None

Workaround Description

No response

Additional Context

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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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