Disable test on -f32::NAN which fails on riscv64. The exact cause still needs investigation. . Justification: Rust does not guarantee that NaN has a deterministic or portable bit pattern. The current CBOR specification (RFC 8949) doesn not mention -NaN, only suggesting NaN be encoded as 0xf97e00. Unless someone is encoding extra information in its payload, distinguishing "different" NaNs isn't terribly useful.
