autoname: Avoid integer overflow

[KrystalDelusion]

What are the reasons/motivation for this change?

I wouldn't expect a pass like autoname to produce a fatal error. While that is certainly better than undefined behavior, so I'm not opposed to merging this as a first step, how difficult would it be to make autoname generate slightly less exhaustive names when they would otherwise become to long?

Originally posted by @jix in #5081 (comment)

Explain how this is achieved.

Alternative approach to #5081 which leaves the score as-is and only compares the name length as necessary. It also changes the wire score from int to unsigned int so that instead of overflowing if the score is over INT32_MAX/20000, the wire fanout now needs to be over INT32_MAX, and is never dependent on the name length.

This avoids the integer overflow and may be preferable, but the test case from #4983 still crashes.

Also includes a fix for autoname to support selection arguments, matching the behaviour in the help message.

If applicable, please suggest to reviewers how they can test the change.

[KrystalDelusion]

Nix on macos failure should be resolved by #5276