Add a function for internal validation, and use it in the fuzzer

[Dr-Emann]

Fixes #197

Also adds a simd mode for the fuzzer in the hopes that it could find something like #327

[Dr-Emann]

Yep, probably found the same issue:

        FuzzInput {
            ops: [
                MutateLhs(
                    Extend(
                        [
                            Num(
                                77121,
                            ),
                            Num(
                                86957,
                            ),
                            Num(
                                77085,
                            ),
                            Num(
                                116169,
                            ),
                            Num(
                                77907,
                            ),
                            Num(
                                101677,
                            ),
                            Num(
                                72989,
                            ),
                            Num(
                                82259,
                            ),
                        ],
                    ),
                ),
                SwapSides,
                MutateLhs(
                    Extend(
                        [
                            Num(
                                130605,
                            ),
                            Num(
                                73133,
                            ),
                            Num(
                                86920,
                            ),
                            Num(
                                101677,
                            ),
                            Num(
                                82327,
                            ),
                            Num(
                                117021,
                            ),
                            Num(
                                82259,
                            ),
                            Num(
                                65536,
                            ),
                        ],
                    ),
                ),
                Binary(
                    AndNot,
                ),
            ],
            initial_input: [],
        }

[Dr-Emann]

Build is failing because a dependency updated that doesn't support 1.71.1. If we're going to pin to support an older rust version, we probably need to commit a Cargo.lock for that.

[Kerollmops]

Thank you for your PR again @Dr-Emann 🙏

I looked at the COBS crate, and it seems they use v1.73~1.74 std features. I'll bump the MSRV to v.1.80.1 (August 2024). I'll let you rebase once I'm done.

EDIT: PR merged with the MSRV bump. Can you rebase on main, please?

[Kerollmops]

Should we check for equality too, as the Interval is an inclusive range?

[Dr-Emann]

Equality should be valid (because it's an inclusive range). You can have {start:0, end:0} to have a single item in the interval.

[Kerollmops]

Thanks again for your work 😇